Wormhole geometry

Schwarzschild geometry


The Schwarzschild geometry describes the spacetime geometry of empty space surrounding any spherical mass. Karl Schwarzschild derived this geometry at the close of 1915, within a few weeks of Albert Einstein publishing his fundamental paper on the Theory of General Relativity. The history of this discovery and much more is wonderfully recounted in Kip Thorne's book ``Black Holes & Time Warps: Einstein's Outrageous Legacy''.

A description of this embedding diagram appears below.

Try John Walker's Orbit's in Strongly Curved Spacetime for a Java applet which allows you to play around with orbits in the Schwarzschild geometry.

Schwarzschild radius
One of the remarkable predictions of Schwarzschild's geometry was that if a mass M were compressed inside a critical radius rs, nowadays called the Schwarzschild radius, then its gravity would become so strong that not even light could escape. The Schwarzschild radius rs of a mass M is given by
rs = 2 G M / c2
where G is Newton's gravitational constant, and c is the speed of light. For a 30 solar mass object, like the black hole in the fictional star system here, the Schwarzschild radius is about 100 kilometers.

Curiously, the Schwarzschild radius had already been derived (with the correct result, but an incorrect theory) by John Michell in 1783 (this reference is from Erk's Relativity Pages) in the context of Newtonian gravity and the corpuscular theory of light. Michel derived the critical radius by setting the gravitational escape velocity v equal to the speed of light c in the Newtonian formula v2 / 2 = G M / r for the escape velocity v from the surface of a star of mass M and radius r.


Horizon
The Schwarzschild surface, the sphere at 1 Schwarzschild radius, is also called the horizon of a black hole, since an outside observer, even one just outside the Schwarzschild surface, can see nothing beyond the horizon.


Schwarzschild metric
Schwarzschild's geometry is described by the metric (in units where the speed of light is one, c = 1)
ds2 = - ( 1 - rs / r ) dt2 + ( 1 - rs / r )-1 dr2 + r2 do2 .
The quantity ds denotes the invariant spacetime interval, an absolute measure of the distance between two events in space and time, t is a `universal' time coordinate, r is the circumferential radius, defined so that the circumference of a sphere at radius r is 2 pi r, and do is an interval of spherical solid angle.


Embedding diagram
The Schwarzschild geometry is illustrated in the embedding diagram at the top of the page, which shows a 2-dimensional representation of the 3-dimensional spatial geometry at a particular instant of universal time t. One should imagine that objects are confined to move only on the 2-dimensional surface. Each circle actually represents a sphere, of circumference 2 pi r. According to the Schwarzschild metric, the proper radial distance, the actual distance measured by an observer at rest at radius r, between two spheres separated by an interval dr of circumferential radius r is (1 - rs/r)-1/2 dr, which is larger than the radial interval dr expected in a flat, Euclidean geometry. Thus the geometry is `stretched' in the radial direction, as shown in the embedding diagram.

Outside the horizon, the lines in the embedding diagram are `space-like': they would be measured by some actual observer (in this case an observer at rest in the Schwarzschild geometry) as being intervals of space at some instant of the observer's proper time (an observer's proper time is the time actually measured by the observer, as experienced by the observer's brain or recorded by a watch on the observer's wrist).

Inside the horizon, lines in the Schwarzschild embedding diagram change to being `time-like': they represent intervals of time measured at the position of some observer, rather than intervals of space at an instant of some observer's time. That is to say, the lines in the embedding diagram inside the horizon represent possible trajectories of infalling (though not necessarily freely falling) observers.

The shape of the embedding diagram inside the horizon, as drawn at the top of the page, is somewhat arbitrary. The animated dashes do however show correctly intervals of proper time as experienced by an observer infalling along a line of constant Schwarzschild time t.


Gravitational slowing of time
In general relativity, clocks at rest run slower inside a gravitational potential than outside.

In the case of the Schwarzschild metric, the proper time, the actual time measured by an observer at rest at radius r, during an interval dt of universal time is (1 - rs/r)1/2 dt, which is less than the universal time interval dt. Thus a distant observer at rest will observe the clock of an observer at rest at radius r to run more slowly than the distant observer's own clock, by a factor
( 1 - rs / r )1/2 .
This time dilation factor tends to zero as r approaches the Schwarzschild radius rs, which means that someone at the Schwarzschild radius will appear to freeze to a stop, as seen by anyone outside the Schwarzschild radius.


Gravitational redshift


The gravitational slowing of time produces a gravitational redshift of photons. That is, an outside observer will observe photons emitted from within a gravitational potential to be redshifted to lower frequencies, or equivalently to longer wavelengths.

Conversely, an observer at rest in a gravitational potential will observe photons from outside to be blueshifted to higher frequencies, shorter wavelengths.

In the case of the Schwarzschild metric, a distant observer at rest will observe photons emitted by a source at rest at radius r to be redshifted so that the observed wavelength is larger by a factor

( 1 - rs / r )-1/2

than the emitted wavelength. The redshift factor tends to infinity as r approaches the Schwarzschild radius rs, which means that someone at the Schwarzschild radius will appear infinitely redshifted, as seen by anyone outside the Schwarzschild radius.
That the redshift factor is the same as the time dilation factor (well, so one's the reciprocal of the other, but that's just because the redshift factor is, conventionally, a ratio of wavelengths rather than a ratio of frequencies) is no coincidence. Photons are a good clocks. When a photon is redshifted, its frequency, the rate at which it ticks, slows down.

In the illustration shown, a source at rest at 1.18 Schwarzschild radii emits light rays with the same initial wavelength in 6 equally spaced directions. The light ray going out is redshifted, while the rays falling in become blueshifted, from the point of view of observers at rest in the Schwarzschild geometry. Five of the 6 rays end up falling into the black hole (the two yellow rays would fall in, but I cut them off so they wouldn't block the view).


No stationary frames inside the Schwarzschild radius
According to the Schwarzschild metric, at the Schwarzschild radius rs, proper radial distance intervals become infinite, and proper time passes infinitely slowly. Inside the Schwarzschild radius, proper radial distances and proper times appear to become imaginary (that is, the square root of a negative number).

Historically, it took decades before this strange behaviour was understood properly (see again Kip Thorne's book ``Black Holes and Time Warps'' for an account). The problem with the Schwarzschild metric is that it describes the geometry as measured by observers at rest. It is now realized that once inside the Schwarzschild radius, there can be no observers at rest: everything plunges inevitably to the central singularity. In effect, the very fabric of spacetime falls to the singularity, carrying everything with it. No pressure can withstand the inexorable collapse.

To paraphrase Misner, Thorne & Wheeler (1973, ``Gravitation'', p. 823), that same unseen power of the world which impels everyone from age 20 to 40, and from 40 to 80, impels objects inside the horizon irresistably towards the singularity.

Answer to the quiz question 8: False. The Schwarzschild metric remains valid inside the Schwarzschild radius. It is fine to perform mathematical calculations using the Schwarzschild metric. Inside the Schwarzschild radius, if you transform to frames of reference which fall inward (or outward, for a white hole!) faster than the speed of light, then the geometry becomes `normal' again.


Schwarzschild spacetime diagram


This spacetime diagram illustrates the temporal geometry of the Schwarzschild metric, at the expense of suppressing information about the spatial geometry. By comparison, the embedding diagram at the top of the page illustrated the spatial geometry, while suppressing information about the temporal geometry.

The horizontal axis represents radial distance, while the vertical axis represents time. The cyan vertical line is the central singularity, at zero radius, while the red vertical line is the horizon, at one Schwarzschild radius. Yellow and ochre lines are the worldlines of light rays moving radially inward and outward respectively. Each point at radius r in the spacetime diagram represents a 3-dimensional spatial sphere of circumference 2 pi r. Dark purple and blue lines are respectively lines of constant Schwarzschild time and constant circumferential radius.

The Schwarzschild spacetime geometry appears ill-behaved at the horizon, the Schwarzschild radius (vertical red line). However, the pathology is an artefact of the Schwarzschild coordinate system. Spacetime itself is well-behaved at the Schwarzschild radius, as can be ascertained by computing the components of the Riemann curvature tensor, all of whose components remain finite at the Schwarzschild radius.

The curious change in the character of the Schwarzschild geometry inside versus outside the horizon can be seen in the spacetime diagram. Whereas outside the horizon infalling and outgoing light rays move generally upward, in the direction of increasing Schwarzschild time, inside the horizon infalling and outgoing light rays move generally leftward, toward the singularity.

General Relativity permits an arbitrary relabelling of coordinates. Some coordinate systems which behave better at the Schwarzschild radius are illustrated below.

Free-fall spacetime diagram


Free-fall coordinates reveal that the Schwarzschild geometry looks like ordinary flat space, with the distinctive feature that space itself is flowing radially inwards at the Newtonian escape velocity
v = (2 G M / r)1/2 .
The infall velocity v passes the speed of light c at the horizon.

Picture space as flowing like a river into the black hole. Imagine light rays, photons, as canoes paddling fiercely in the current. Outside the horizon, photon-canoes paddling upstream can make way against the flow. But inside the horizon, the space river is flowing inward so fast that it beats all canoes, carrying them inevitably towards their ultimate fate, the central singularity.

Does the notion that space inside the horizon of a black hole falls faster than the speed of light violate Einstein's law that nothing can move faster than light? No. Einstein's law applies to the velocity of objects moving in spacetime as measured with respect to locally inertial frames. Here it is space itself that is moving.

The free-fall metric expresses mathematically the above physical assertions. The free-fall metric is
ds2 = - dtff2 + (dr + v dtff)2 + r2 do2
where r is the usual Schwarzschild radial coordinate, and the free-fall time coordinate tff is the proper time experienced by persons who free-fall radially inward, at velocity dr/dtff = - v, from zero velocity at infinity:
tff = t + 2 r1/2 + ln|(r1/2 - 1)/(r1/2 + 1)|
in units where the speed of light and the Schwarzschild radius are both unity, c = 1 and rs = 1. The free-fall metric shows that the spatial geometry is flat, having spatial metric dr2 + r2 do2, on hypersurfaces of fixed free-fall time, dtff = 0.

The colouring of lines in the free-fall spacetime diagram is as in the Schwarzschild case, with the addition of green lines which are worldlines of observers who free fall radially from zero velocity at infinity, and horizontal dark green lines which are lines of constant free-fall time tff.

Watch Schwarzschild morph into free-fall (41K GIF); or same morph, double-size on screen (same 41K GIF).

Eddington-Finkelstein spacetime diagram


Eddington-Finkelstein coordinates differ from Schwarzschild coordinates only in the relabelling of the time. The relabelling is arranged so that radially infalling light rays (yellow lines) move at 45o in the spacetime diagram. Finkelstein time tF is related to Schwarzschild time t by

tF = t + ln|r - 1|

in units where the speed of light and the Schwarzschild radius are one, c = 1 and rs = 1.
The colouring of lines is as in the Schwarzschild case: the red line is the horizon, the cyan line at zero radius is the singularity, yellow and ochre lines are respectively the wordlines of radially infalling and outgoing light rays, while dark purple and blue lines are respectively lines of constant Schwarzschild time and constant circumferential radius.

Watch Schwarzschild morph into Finkelstein (28K GIF); or same morph, double-size on screen (same 28K GIF).

Watch Finkelstein morph into free-fall (38K GIF); or same morph, double-size on screen (same 38K GIF).

Kruskal-Szekeres spacetime diagram


Kruskal-Szekeres coordinates show transparently the causal structure of the Schwarzschild geometry. By construction, radially infalling (yellow) or outgoing (ochre) light rays move at 45o leftward or rightward in the Kruskal-Szekeres spacetime diagram.

Watch Finkelstein morph into Kruskal (50K GIF); or same morph, double-size on screen (same 50K GIF).

In addition to the normal horizon (pink-red line from centre to top right), through which light rays (yellow lines) and people can fall, there appears in the Kruskal diagram to be a second horizon, a `past' horizon or antihorizon (red line from bottom right to top left). In the Schwarzschild or Finkelstein coordinate systems, this antihorizon existed only in the infinite past.

As it happens, lines of constant Schwarzschild time (dark purple) correspond to straight lines passing through the origin (where the horizon and the antihorizon cross) in the Kruskal-Szekeres coordinate system.

How does the Kruskal diagram relate to what happened in the Falling into a Black Hole movie? The red grid on the surface of the black hole in the movie corresponds to the red antihorizon in the Kruskal diagram. When we fell through the horizon in the movie, it appeared that the Schwarzschild surface split into two, and we found ourselves inside the Schwarzschild bubble. The upper Schwarzschild surface of the bubble, coloured white in the movie, is the normal pink-red horizon in the Kruskal diagram. The lower Schwarzschild surface of the bubble, coloured red in the movie, is the red antihorizon in the Kruskal diagram. The place where the upper (white) Schwarzschild surface joined the lower (red) Schwarzschild surface in the movie corresponds to the origin in the Kruskal diagram, where the pink-red horizon and red antihorizon cross.

What lies beyond the antihorizon of the Schwarzschild geometry? The complete Kruskal-Szekeres spacetime diagram, discussed in the section on White Holes and Wormholes, reveals the suprising answer that beyond the antihorizon is another Universe, a second copy of the Schwarzschild geometry, connected to this Universe by a wormhole.

Kruskal-Szekeres metric
Kruskal time tK and radial coordinate rK (respectively the vertical and horizontal coordinate in the Kruskal spacetime diagram) are related to Schwarzschild time t and radial coordinate r, the circumferential radius, by the following transformation. Let R denote what Misner, Thorne & Wheeler (1973, ``Gravitation'') call the `tortoise coordinate'
R = r + ln|r - 1|
(in units where the speed of light and the Schwarzschild radius are both unity, c = 1 and rs = 1). The tortoise coordinate R has the property that radially infalling and outgoing light rays satisfy
R + t = constant
R - t = constant
respectively. Kruskal time tK and Kruskal radius rK are then defined by
rK + tK = 2 e(R + t)/2
rK - tK = ± 2 e(R - t)/2
where the overall sign in the last equation is positive (+) outside the Schwarzschild radius, r > 1, and negative (-) inside the Schwarzschild radius, r < 1. The Kruskal metric is ds2 = r-1 e-r ( - dtK2 + drK2 ) + r2 do2 . The Schwarzschild radial coordinate r, which appears in the factors r-1 e-r and r2 in the Kruskal metric, is to be understood as an implicit function of the Kruskal coordinates tK and rK. The Kruskal metric shows explicitly that the Schwarzschild geometry is well-behaved at the Schwarzschild radius, r = 1. Penrose diagram of the Schwarzschild geometry Penrose invented his diagrams as a device for depicting the complete causal structure of any given geometry. Penrose diagrams map everything in the geometry on to a finite diagram, including points at infinite distance and in the infinite past and future. Light rays (null geodesics) are arranged so that they always point at 45o from the upward vertical. Penrose diagrams are spacetime diagrams in which the metric takes a certain generic, although not unique, form. In the Penrose diagram of the Schwarzschild geometry at left, the Penrose time tP and radial rP coordinate are related to the Kruskal time tK and radial rK coordinate by rP + tP = rK + tK 2 + |rK + tK| , rP - tP = rK - tK 2 + |rK - tK| .

The Orion Nebula

The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated south[b] of Orion's Belt. It is one of the brightest nebulae, and is visible to the naked eye in the night sky. M42 is located at a distance of 1,344 ± 20 light years[2][5] and is the closest region of massive star formation to Earth. The M42 nebula is estimated to be 24 light years across. Older texts frequently referred to the Orion Nebula as the Great Nebula in Orion or the Great Orion Nebula.
The Orion Nebula is one of the most scrutinized and photographed objects in the night sky, and is among the most intensely studied celestial features.[6] The nebula has revealed much about the process of how stars and planetary systems are formed from collapsing clouds of gas and dust. Astronomers have directly observed protoplanetary disks, brown dwarfs, intense and turbulent motions of the gas, and the photo-ionizing effects of massive nearby stars in the nebula. There are also supersonic "bullets" of gas piercing the dense hydrogen clouds of the Orion Nebula. Each bullet is ten times the diameter of Pluto's orbit and tipped with iron atoms glowing bright blue. They were probably formed one thousand years ago from an unknown violent event.

Intro

The Galactic Alignment is the alignment of the December solstice sun with the Galactic equator. This alignment occurs as a result of the precession of the equinoxes.
Precession is caused by the earth wobbling very slowly on its axis and shifts the position of the equinoxes and solstices one degree every 71.5 years. Because the sun is one-half of a degree wide, it will take the December solstice sun 36 years to precess through the Galactic equator (see diagram below).
The precise alignment of the solstice point (the precise center-point of the body of the sun as viewed from earth) with the Galactic equator was calculated to occur in 1998 (Jean Meeus, Mathematical Astronomy Morsels, 1997).
Thus, the Galactic Alignment "zone" is 1998 +/- 18 years = 1980 - 2016. This is "era-2012."
This Galactic Alignment occurs only once every 26,000 years, and was what the ancient Maya were pointing to with the 2012 end-date of their Long Count calendar.

These are the astronomical facts of the matter. From a larger perspective, we can visualize the 2012 Galactic Alignment in the following way:

Position A is where the December solstice sun was in relation to the Milky Way some 3,000 years ago. Position B is 1,500 years ago. And position C is "era-2012", when the December solstice sun has converged, as a result of the precession of the equinoxes, with the exact center-line of the Milky Way (the Galactic equator). Notice that the place of alignment is where the 'nuclear bulge' of the Galactic Center is located.
A long awaiting digital portrayal of precession and galactic alignments is now available on Nick Fiorenza's web site.

2012 Astronomical Alignment

As a brief review of the some of the most basic of these natural cycles, we will begin with the rotation of the Earth on its axis. Because the Earth rotates one complete revolution every 24 hours we observe the reoccurring periods of day and night.

Unfortunately there are surprisingly large numbers of people today that still do not understand that this daily cycle is caused by the motion of the Earth and not by anything the Sun is doing. This could somewhat be explained by the fact that our linguistic customs lag centuries behind our scientific understanding, and we continue to speak in terms of sunrise and sunsets.

Be that as it may, the next cycle we will look at is based not on the motion of the Earth but of the Moon. The Moon revolves around the Earth every 29.5 days, giving us the concept of the month as it appears in its different phases from New Moon to Full and once again back to New.

Then there is the observable cycle of the year, as the Earth dances around the Sun in an elliptical orbit taking 365.25 days to complete one revolution.

As people continued to observe the heavenly bodies they also began to notice that some of the bright lights in the sky moved while others stayed relatively stationary. These wandering bodies we have come to know as the planets, and various people all over the world took a special interest in their particular movement and cycles, spawning a huge number of stories, myths and legends.

To those early astronomers who kept records of the movement of the Sun, Moon and Planets one of the greatest mysteries that they observed was the fact that every year they would wait for the Sun to appear on the Spring Equinox or Winter Solstice at a specific place on the horizon signaling the New Year.

Over time they were dismayed to find that the Sun no longer appeared in the same place it did just 70 years before, but had moved one full degree (the equivalent to the diameter of the Sun - times two). This slow movement, called the Precession of the Equinox, causes the Equinox Sun to appear to slip backward against the backdrop of the stars.

Astronomers have now managed to figure out that the Earth is not a perfect sphere by any means. It’s actually a bit flattened at the poles and has a bulge at the equator. As a result, the gravitational pull of the Moon and the Sun exert an uneven influence on the Earth. Their gravitational forces try to pull the equatorial bulge toward them. Because the Earth is spinning these forces make the axis of the Earth wobble, shifting ever so slowly. Gradually the polar axis that was at one time aligned with a particular star begins to shift until it is aligned with another star.

Right now the Earth’s axis at the North Pole points to the star Polaris – which appropriately we call the Pole Star. But 5,000 years ago the north celestial pole aligned to the star called Alpha Draconis. Eight thousand years in the future the pole star will be Vega.



This Precessional movement then is the same motion responsible for the shift of the location of the Equinoxes and the Solstices. The ancient astronomers detected the long term Precessional motion of the Sun through the back drop of the constellations and calculated the length of this Cycle to around 25,600 to 26,000 years.

This means that the Sun that marks the Spring Equinox which now appears in front of the background of stars in the constellation of Pisces, in about 500 years will rise in the constellation of Aquarius. It will continue to shift backwards through the various constellations Capricorn, Sagittarius, etc., until in about 26,000 years it will arrive back to the exact same point in Pisces.

The understanding of this Precession of the Equinox then gave rise to the many myths and legends of the different World Ages. As the Processional movement continued to shift the Equinox into a new constellation, various cultures perceived this as a New Age or New World. As the Spring Equinox Sun appeared to rise in the constellation of Taurus, people perceived this as the Age of the Bull; the Age of the Ram as it rose in the constellation of Aries; the Age of the Fish as it rose in Pisces and so on.

At one time many civilizations on Earth were aware of this natural cycle of the Earth and incorporated it into their cosmologies and concepts of Time in various ways. Each one reflecting a slightly different interpretation and meaning, but in their different ways they all held the Precessional Cycle as involving nothing less than the Cosmic process of Life’s evolution, subtly influencing all of Earth’s Life Forms to move to higher levels of organization and complexity. It came to symbolize the Spiritual Process of Unfolding Consciousness on our planet.

What is important here is that this belief was actually based on an observable astronomical cycle: every 72 years the Solstice and Equinox Sun appeared to move backward through the constellations one degree - as a hand on a clock indicating the hours of the day. In this Cosmic Clock however, the hand or marker in motion is the specific location of the Equinox or Solstice Sunrise, while the face of the clock is represented by the relatively stationary constellations of the stars.

With this in mind then, we will now turn our attention to how this Precessional Cycle became incorporated into the Mayan Cosmology and how it relates to their long count calendar and specifically to the year 2012.

Perhaps more than any ancient culture that we are aware of at this point, the Mayan people were obsessed with Astronomy. Not only were they able to project their astronomical calculations thousands of years forward and backward in Time, but developed a recyclable Venus calendar that was accurate to one day in 500 years and a table of eclipses that still functions today. They also accurately calculated the solar year out to four decimal places. To accomplish these impressive computations they created a sophisticated system of mathematics utilizing place value and the concept of the zero. And all this while Europe was still wandering around in the Dark Ages.

In a complex culture such as we find with the Maya and considering it spanned a period of almost a thousand years, it is important to remember that there arose different belief systems at different times, some of which were coexisting at the same place. Just as if we were to look at the demographics of say modern New York city, we would find Jews perhaps living besides Moslems, Protestants and Catholics - all entertaining different belief systems.

And so it’s appropriate here to limit our considerations of the Mayan culture to only those beliefs that lend meaning and significance to the auspicious date indicated in their long count calendar - Dec.21, 2012.

As we more sharply focus in on this date, we find that one of the indicators to its probable significance is that it specifically designates the Winter Solstice. As this is our starting point in our analysis then, let’s take a closer look as to what this might mean.

First of all it is good to be aware that around the world in various past cultures, each one designated a specific time to mark the beginning of their New Year. In ancient Sumeria and Babylon the New Year began with the Spring Equinox. In Israel the New Year was gradually shifted to the Equinox in the Fall, while in Northern Europe, New Year was celebrated at the time of Winter Solstice. We still observe this particular New Year tradition, but add a few extra days so that now our New Year begins on January 1st.

In the context of this tradition then, the Winter Solstice on December 21 was celebrated as the Sun’s birthday. It is the longest night of the year and therefore the shortest day of the year. It represented the ultimate power of the dark forces of Nature: the long winter night when things appeared to be dead and still. And out of the depths of this longest night the new Sun was born. From this point on, the power of the light grows in strength and the days slowly begin to grow longer.

A White Dwarf

A white dwarf, also called a degenerate dwarf, is a small star composed mostly of electron-degenerate matter. They are very dense; a white dwarf's mass is comparable to that of the Sun and its volume is comparable to that of the Earth. Its faint luminosity comes from the emission of stored thermal energy.[1] In January 2009, Research Consortium on Nearby Stars project counted eight white dwarfs among the hundred nearest star systems of the sun.[2] The unusual faintness of white dwarfs was first recognized in 1910 by Henry Norris Russell, Edward Charles Pickering, and Williamina Fleming;[3], p. 1 the name white dwarf was coined by Willem Luyten in 1922.[4]
White dwarfs are thought to be the final evolutionary state of all stars whose mass is not high enough to supernova—over 97% of the stars in our galaxy.[5], §1. After the hydrogen-fusing lifetime of a main-sequence star of low or medium mass ends, it will expand to a red giant which fuses helium to carbon and oxygen in its core by the triple-alpha process. If a red giant has insufficient mass to generate the core temperatures required to fuse carbon, an inert mass of carbon and oxygen will build up at its center. After shedding its outer layers to form a planetary nebula, it will leave behind this core, which forms the remnant white dwarf.[6] Usually, therefore, white dwarfs are composed of carbon and oxygen. It is also possible that core temperatures suffice to fuse carbon but not neon, in which case an oxygen-neon–magnesium white dwarf may be formed.[7] Also, some helium white dwarfs[8][9] appear to have been formed by mass loss in binary systems.
The material in a white dwarf no longer undergoes fusion reactions, so the star has no source of energy, nor is it supported by the heat generated by fusion against gravitational collapse. It is supported only by electron degeneracy pressure, causing it to be extremely dense. The physics of degeneracy yields a maximum mass for a nonrotating white dwarf, the Chandrasekhar limit—approximately 1.4 solar masses—beyond which it cannot be supported by degeneracy pressure. A carbon-oxygen white dwarf that approaches this mass limit, typically by mass transfer from a companion star, may explode as a Type Ia supernova via a process known as carbon detonation.[1][6] (SN 1006 is thought to be a famous example.)
A white dwarf is very hot when it is formed but since it has no source of energy, it will gradually radiate away its energy and cool down. This means that its radiation, which initially has a high color temperature, will lessen and redden with time. Over a very long time, a white dwarf will cool to temperatures at which it will no longer be visible, and become a cold black dwarf.[6] However, since no white dwarf can be older than the age of the Universe (approximately 13.7 billion years),[10] even the oldest white dwarfs still radiate at temperatures of a few thousand kelvins, and no black dwarfs are thought to exist yet.[1][5]

Physics of the Impossible 5

Class II impossibilities
Class II Impossibilities are “technologies that sit at the very edge of our understanding of the physical world," possibly taking thousands or millions of years to become available.[8]
Such a technology is time travel. Einstein’s equations do show that time travel is possible. However, this would not be developed for a time scale of centuries or even millennia from now. This would make it a Class II impossibility. The two major physical hurdles are energy and stability. Traveling through time would require the entire energy of a star or black hole. Questions of stability are: will the radiation from such a journey kill you and will the “aperture” remain open so you can get back?[7] According to Dr. Kaku in an interview, “the serious study of the impossible has frequently opened up rich and unexpected domains of science”.[9]
[edit]Class III impossibilities
Class III Impossibilities are “technologies that violate the known laws of physics." Kaku writes about only two of these, perpetual motion machines and precognition. Development of these technologies would represent a fundamental shift in human understanding of physics.[3][8]

Physics of the Impossible 4

Class I impossibilities
Class I Impossibilities are "technologies that are impossible today, but that do not violate the known laws of physics." Kaku speculates that these technologies may become available in some limited form in a century or two.[5]
A future technology that may be seen in within a lifetime is a new advanced stealth technology. This is a Class I Impossibility. In 2006, Duke University and Imperial College were able to bend microwaves around an object so that it would appear invisible in the microwave range.[1] The object is like a boulder in a stream. Downstream the water has converged in such a way that there is no evidence of a boulder up stream. Likewise, the microwaves converge in such a way, that to an observer from any direction, there is no evidence of an object. In 2008 two groups, one at Caltech and the other in Germany, were able to bend red light and blue-green of the visible spectrum. This made the object appear invisible in the red and blue green light range. However, this was only at the microscopic level.[1]
Teleportation, is a class I impossibility, in that it doesn’t violate the laws of physics, and could possibly exist on the time scale of a century. Today scientists are able to teleport only information at the atomic level. Information can be teleported from Atom A to Atom B, for example. But this is nothing like beaming Captain Kirk down to a planet and back. In order to do that a person would have to be dissolved atom by atom then rematerialized at the other end. On the scale of a decade it will probably be possible to teleport the first molecule, and maybe even a virus.[7]

Physics of the Impossible 3

Types of impossibilities

Each chapter is named by a possible, or improbable, technology of the future. After a look at the development of today's technology, there is discussion as to how this advanced technology might become a reality. Chapters become somewhat more general towards the end of the book. Some of our present day technologies are explained, and then extrapolated into futuristic applications. In the future, current technologies are still recognizable, but in a slightly altered form. For example, when discussing force fields of the future, Dr. Kaku writes about cutting edge laser technology, and newly developed plasma windows. These are two of several technologies, which he sees as required for creating a force field. To create a force field these would be combined in a slightly altered form, such as more precise or more powerful. Furthermore, this discussion on force fields, as well as on the pantheon of highly advanced technologies, remains as true to the original concepts (as in how the public generally imagines advanced technologies) as possible, while remaining practical.[5][6] Kaku concludes his book with a short epilogue detailing the newest frontiers in physics and how there is still much more to be learned about physics and our universe.
Kaku writes that since scientists understand the basic laws of physics today they are able to perceive or imagine a basic outline of future technologies that might work. Kaku writes: "Physicists today understand the basic laws [of physics] extending over a staggering forty three orders of magnitude, from the interior of the proton out to the expanding universe."[5] He goes on to say that physicists can discern between future technologies that are merely improbable and those technologies that are truly impossible. He uses a system of Class I, Class II, and Class III to classify these science-fictional future technologies that are believed to be impossible today.

Physics of the Impossible 2

The concept of impossibility

According to Kaku, technological advances that we take for granted today were declared impossible 150 years ago. William Thomson Kelvin (1824–1907), a mathematical physicist and creator of the Kelvin scale said publicly that “heavier than air” flying machines were impossible. “He thought X-rays were a hoax, and that radio had no future.”[4] Likewise, Ernest Rutherford (1871–1937), a physicist who experimentally described the atom, thought the atom bomb was impossible and he compared it to moonshine (a crazy or foolish idea). Televisions, computers, and the internet would seem incredibly fantastic to the people of the turn of the 20th century. Black holes were considered science fiction and even Einstein showed that black holes could not exist. 19th century science had determined that it was impossible for the earth to be billions of years old. Even in the 1920s and 1930s, Robert Goddard was scoffed at because it was believed that rockets would never be able to go into space.[4]
Such advances were considered impossible because the basic laws of physics and science were not understood as well as they are understood today. Kaku states that “as a physicist [he] learned that the impossible is often a relative term.” By this definition of "impossible", he poses the question "Is it not plausible to think that we might someday build space ships that can travel distances of light years, or think that we might teleport ourselves from one place to the other?"

Physics of the Impossible 1

hysics of the Impossible: A Scientific Exploration Into the World of Phasers, Force Fields, Teleportation, and Time Travel is a 2008 book by theoretical physicist Michio Kaku. Kaku uses discussion of speculative technologies to introduce topics of fundamental physics to the reader. The topic of invisibility becomes a discussion on why the speed of light is slower in water than a vacuum, that electromagnetism is similar to ripples in a pond, and Kaku discusses newly-developed composite materials. The topic of Star Trek "phasers" becomes a lesson on how lasers work and how laser-based research is conducted. With each discussion of science fiction technology topics he also "explains the hurdles to realizing these science fiction concepts as reality".

Neutrinos

A neutrino (Italian pronunciation: [neuˈtriːno], meaning "small neutral one"; English pronunciation: /njuːˈtriːnoʊ/) is an elementary particle that usually travels close to the speed of light, is electrically neutral, and is able to pass through ordinary matter almost undisturbed. This makes neutrinos extremely difficult to detect. Neutrinos have a very small, but nonzero mass. They are denoted by the Greek letter ν (nu).
Neutrinos are created as a result of certain types of radioactive decay or nuclear reactions such as those that take place in the Sun, in nuclear reactors, or when cosmic rays hit atoms. There are three types, or "flavours", of neutrinos: electron neutrinos, muon neutrinos and tau neutrinos; each type also has a corresponding antiparticle, called antineutrinos. Electron neutrinos (or antineutrinos) are generated whenever protons change into neutrons (or vice versa), the two forms of beta decay. Interactions involving neutrinos are mediated by the weak interaction.
Most neutrinos passing through the Earth emanate from the Sun, and more than 50 trillion solar neutrinos pass through an average human body every second.

Dark Matter

In astronomy and cosmology, dark matter is matter that is inferred to exist from gravitational effects on visible matter and background radiation, but is undetectable by emitted or scattered electromagnetic radiation. Its existence was hypothesized to account for discrepancies between measurements of the mass of galaxies, clusters of galaxies and the entire universe made through dynamical and general relativistic means, and measurements based on the mass of the visible "luminous" matter these objects contain: stars and the gas and dust of the interstellar and intergalactic media. According to observations of structures larger than galaxies, as well as Big Bang cosmology interpreted under the "Friedmann equations" and the "FLRW metric", dark matter accounts for 23% of the mass-energy density of the observable universe, while the ordinary matter accounts for only 4.6% (the remainder is attributed to dark energy). From these figures, dark matter constitutes 80% of the matter in the universe, while ordinary matter makes up only 20%.
Dark matter was postulated by Fritz Zwicky in 1934 to account for evidence of "missing mass" in the orbital velocities of galaxies in clusters. Subsequently, other observations have indicated the presence of dark matter in the universe, including the rotational speeds of galaxies, gravitational lensing of background objects by galaxy clusters such as the Bullet Cluster, and the temperature distribution of hot gas in galaxies and clusters of galaxies.
Dark matter plays a central role in state-of-the-art modeling of structure formation and galaxy evolution, and has measurable effects on the anisotropies observed in the cosmic microwave background. All these lines of evidence suggest that galaxies, clusters of galaxies, and the universe as a whole contain far more matter than that which interacts with electromagnetic radiation. The largest part of dark matter, which does not interact with electromagnetic radiation, is not only "dark" but also, by definition, utterly transparent.
As important as dark matter is believed to be in the universe, direct evidence of its existence and a concrete understanding of its nature have remained elusive. Though the theory of dark matter remains the most widely accepted theory to explain the anomalies in observed galactic rotation, some alternative theoretical approaches have been developed which broadly fall into the categories of modified gravitational laws, and quantum gravitational laws.

Cassini-Huygens Trajectory

The initial gravitational-assist trajectory of Cassini–Huygens is the process whereby an insignificant mass approaches a significant mass "from behind" and "steals" some of its orbital momentum. The significant mass, usually a planet, loses a very small proportion of its orbital momentum to the insignificant mass, the space probe in this case. However, due to the space probe's small mass, this momentum transfer gives it a relatively large momentum increase in proportion to its initial momentum, speeding up its travel through outer space.
The Cassini–Huygens space probe performed two gravitational assist fly-bys at Venus, one more fly-by at the Earth, and a final fly-by at Jupiter.

Cassini-Huygens (Saturn orbiter)

http://www.nasa.gov/mission_pages/cassini/main/index.html

Cassini–Huygens is a joint NASA/ESA/ASI robotic spacecraft mission currently studying the planet Saturn and its many natural satellites. The spacecraft consists of two main elements: the NASA-designed and -constructed Cassini orbiter, named for the Italian-French astronomer Giovanni Domenico Cassini, and the ESA-developed Huygens probe, named for the Dutch astronomer, mathematician and physicist Christiaan Huygens. The complete Cassini space probe was launched on October 15, 1997, and after a long interplanetary voyage, it entered into orbit around Saturn on July 1, 2004. On December 25, 2004, the Huygens probe was separated from the orbiter at approximately 02:00 UTC. Then, it reached Saturn's moon Titan on January 14, 2005, when it made a descent into Titan's atmosphere, and downwards to the surface, radioing scientific information back to the Earth by telemetry. On April 18, 2008, NASA announced a two-year extension of the funding for ground operations of this mission, at which point it was renamed to Cassini Equinox Mission.[1] This was again extended in February 2010 and the mission may potentially continue until 2017. Cassini is the fourth space probe to visit Saturn and the first to enter orbit.
16 European countries and the United States make up the team responsible for designing, building, flying and collecting data from the Cassini orbiter and Huygens probe. The mission is managed by NASA’s Jet Propulsion Laboratory in the United States, where the orbiter was designed and assembled. Development of the Huygens Titan probe was managed by the European Space Research and Technology Centre, whose prime contractor for the probe was the Alcatel company in France. Equipment and instruments for the probe were supplied from many countries. The Italian Space Agency (ASI) provided the Cassini probe's high-gain radio antenna, and a compact and lightweight radar, which acts in multipurpose as a synthetic aperture radar, a radar altimeter, and a radiometer.

Evidence for the big bang

Evidence for the Big Bang


The CMB signal detected by Penzias and Wilson, a discovery for which they later won a Nobel Prize, is often described as the “echo” of the Big Bang. Because if the Universe had an origin, it would leave behind a signature of the event, just like an echo heard in a canyon represents a “signature” of the original sound. The difference is that instead of an audible echo, the Big Bang left behind a heat signature throughout all of space.

Another prediction of the Big Bang theory is that the Universe should be receding from us. Specifically, any direction we look out into space, we should see objects moving away from us with a velocity proportional to their distance away from us, a phenomenon known as the red shift.


http://scienceblogs.com/startswithabang/upload/2010/06/your_theory_doesnt_do_everythi/big-bang.jpg

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Dark matter

The Alpha Magnetic Spectrometer (AMS), an experiment that will search for antimatter and dark matter in space, leaves CERN August 24 on the next leg of its journey to the International Space Station. The AMS detector is being transported from CERN to Geneva International Airport in preparation for its planned departure from Switzerland on 26 August, when it will be flown to the Kennedy Space Center in Florida on board a US Air Force Galaxy transport aircraft.

AMS will examine fundamental issues about matter and the origin and structure of the Universe directly from space. Its main scientific target is the search for dark matter and antimatter, in a programme that is complementary to that of the Large Hadron Collider.

Last February the AMS detector travelled from CERN to the European Space Research and Technology Centre (ESTEC) in Noordwijk (Netherlands) for testing to certify its readiness for travel into space. Following the completion of the testing, the AMS collaboration decided to return the detector to CERN for final modifications. In particular, the detector's superconducting magnet was replaced by the permanent magnet from the AMS-01 prototype, which had already flown into space in 1998. The reason for the decision was that the operational lifetime of the superconducting magnet would have been limited to three years, because there is no way of refilling the magnet with liquid helium, necessary to maintain the magnet's superconductivity, on board the space station. The permanent magnet, on the other hand, will now allow the experiment to remain operational for the entire lifetime of the ISS.

Following its return to CERN, the AMS detector was therefore reconfigured with the permanent magnet before being tested with CERN particle beams. The tests were used to validate and calibrate the new configuration before the detector leaves Europe for the last time.
Upon arrival at the Kennedy Space Center, AMS will be installed in a clean room for a few more tests. A few weeks later, the detector will be moved to the space shuttle. NASA is planning the last flight of the space shuttle programme, which will carry AMS into space, for the end of February 2011.

Once docked to the ISS, AMS will search for antimatter and dark matter by measuring cosmic rays. Data collected in space by AMS will be transmitted to Houston (USA) and on to CERN's Prévessin site, where the detector control centre will be located, and to a number of regional physics analysis centres set up by the collaborating institutes.

News

Joint Dark Energy Mission a Top Priority for NASA, Says NRC

BERKELEY, CA — The National Research Council's Beyond Einstein Program Assessment Committee has recommended that the Joint Dark Energy Mission (JDEM), jointly supported by the National Aeronautics and Space Administration and the Department of Energy, be the first of NASA's Beyond Einstein cosmology missions to be developed and launched.

SNAP, the SuperNova/Acceleration Probe, is one of three concepts competing for NASA and DOE's Joint Dark Energy Mission (JDEM).

One of the three competing projects in the JDEM program is Lawrence Berkeley National Laboratory's SuperNova/Acceleration Probe, or SNAP, a versatile space-borne observatory with a powerful two-meter-class telescope and a half-billion pixel imager, designed to study dark energy by recording the distance and redshift of some 2,000 Type Ia supernovae a year and mapping the sky with unprecedented resolution. Dark energy is the name given to the mysterious entity which is causing the universe to expand ever more rapidly. It accounts for nearly three-quarters of all the energy in the universe.

The recommendations of NRC's Beyond Einstein Program Assessment Committee (BEPAC), posted on the internet Sept. 5, follow nearly a year of intensive study of the five proposed missions in the Beyond Einstein program. Due to budget constraints and technological readiness only one such mission can be started at this time, so NASA and DOE requested in August, 2006 that the NRC, while assessing the program as a whole, recommend which mission should be developed and launched first.

"NASA and DOE have moved forward together since joining forces on the Joint Dark Energy Mission four years ago, including their support for Berkeley Lab's approach to the mission, SNAP," says Steven Chu, Director of the Department of Energy's Lawrence Berkeley National Laboratory. "By recommending that JDEM be the first Beyond Einstein mission to be launched, the National Research Council has assured that the two agencies will be partners in investigating one of the most pressing scientific questions of the 21st century. We look forward to the agencies' moving forward upon receiving the NRC Committee Report."

"It's wonderful to know that NASA will be moving forward with this exciting project as a result of the committee's recommendation that JDEM be the first mission to fly," says Saul Perlmutter, a member of Berkeley Lab's Physics Division and Professor of Physics at the University of California at Berkeley. "Each of the highly ranked Beyond Einstein projects will contribute greatly to our understanding of the universe, yet few questions are more fundamental or pressing than the mysterious nature of dark energy, which accounts for some three-quarters of the energy density of our universe — but about which we know almost nothing."

"It is not surprising that the BEPAC reaffirmed the importance of the exciting science that connects quarks with the Cosmos — the stunning scientific opportunities, from understanding how the Universe began to unraveling the mystery of the dark energy to probing black holes, speak for themselves," says Michael Turner, Professor of Physics and of Astronomy and Astrophysics at the University of Chicago, who led an NRC Quarks-to-the-Cosmos study which stimulated the Beyond Einstein program. However, says Turner, "Today's real milestone is the selection of the Joint Dark Energy Mission as the first of multiple missions in NASA's Beyond Einstein program.... JDEM will harness the powerful combination of two science agencies, DOE and NASA, and the scientists they support, to shed light on the most abundant and most mysterious stuff in the Universe. JDEM will set a high mark for the Beyond Einstein missions that follow."

The JDEM Mission to Explore Dark Energy

Three concepts for a JDEM mission have been proposed: the SuperNova/Acceleration Probe (SNAP), the Dark Energy Space Telescope (DESTINY), and the Advanced Dark Energy Physics Telescope (ADEPT).

SNAP is being developed by an international collaboration led by principal investigator Perlmutter and by co-principal investigator and project director Michael Levi, of Lawrence Berkeley National Laboratory's Physics Division and UC Berkeley's Space Sciences Laboratory. In addition to Berkeley Lab, partner institutions include the Space Sciences Laboratory; the French Space Agency, the Centre National D'Etudes Spatiales; and a number of U.S. and Canadian universities. DESTINY is led by Tod Lauer of the National Optical Astronomy Observatory, and ADEPT is led by Charles Bennett of Johns Hopkins University.

Dark energy, which accounts for about three-quarters of the energy density of the universe, was unknown before 1998. Early that year two international teams, the Supernova Cosmology Project based at Lawrence Berkeley National Laboratory and led by Perlmutter, and the High-Z Supernova Search Team led by Brian Schmidt of the Australian National University, independently announced their discovery that the expansion of the universe is not slowing from the contracting force of gravity but is in fact growing more and more rapidly. The cause of accelerating expansion was soon named dark energy.

Perlmutter and Schmidt and the members of their teams share the 2007 Gruber Cosmology Prize for their discovery. Perlmutter, Adam Riess of Johns Hopkins University, and Schmidt shared the 2006 Shaw Prize in Astronomy for this discovery. Perlmutter also received the 2006 International Antonio Feltrinelli Prize in the Physical and Mathematical Sciences, awarded once every five years, for his work leading to the discovery of dark energy.

"Evidence for dark energy came almost ten years ago," Michael Turner remarks, "and the mystery of this weird stuff with repulsive gravity which controls the expansion of the Universe and its destiny has captured the attention of physicists, astronomers and the public alike." Scientists still cannot say whether dark energy has a constant value or is changing over time — or even whether dark energy is an illusion, with the accelerating expansion of the universe a consequence of a failure of general relativity.

SNAP, the SuperNova/Acceleration Probe

It was in 1999, soon after the discovery of dark energy, that members of the Supernova Cosmology Project joined with their colleagues to devise a space-based experiment, SNAP, to reveal its nature. Intensive research and development efforts for SNAP have been vigorously supported by DOE's Office of Science since it was proposed, and by NASA since 2003, when it joined with DOE to pursue the Joint Dark Energy Mission.

In May, 2006, NASA, DOE, and NSF's Dark Energy Task Force reported that different techniques for measuring dark energy in combination "have substantially more statistical power, much more ability to discriminate among dark energy models, and more robustness to systematic errors than any single technique."

"SNAP will investigate dark energy using two independent and powerful techniques," says Perlmutter, SNAP's principal investigator. "The best proven and most powerful current technique is to determine changes in the universe's expansion rate by comparing the redshift and distance of Type Ia supernovae, of which SNAP will find some 2,000 a year. But we are also targeting the most promising complementary technique, called 'weak gravitational lensing.'"

Levi, SNAP's co-principal investigator, explains that "Weak gravitational lensing has been part of the SNAP concept since its beginning in 1999. SNAP will make a high-resolution map of the sky covering an area 2,000,000 times larger than the Hubble Deep Field. This map will be sensitive to the minute distortions of distant galaxy shapes when their light passes through uneven distributions of matter — a phenomenon called 'weak lensing.' Weak lensing promises a powerful way to measure the distribution of dark matter and to probe dark energy's effect on the growth structure of the universe. The huge survey map will also provide astronomers with an unparalleled wealth of high-resolution images never before seen."

NASA incorporated JDEM into the Beyond Einstein program when it was formulated by the agency's Astronomy and Physics Division in 2004. The program eventually focused on five such missions: to detect gravitational waves, provide a more powerful x-ray telescope, investigate models of cosmic inflation, find black holes, and study the nature of dark energy.

Galaxy formation

The formation of galaxies is still one of the most active research areas in astrophysics; and, to some extent, this is also true for galaxy evolution.
Some ideas, however, are now widely accepted.
After the Big Bang, the universe had a period when it was remarkably homogeneous, as can be observed in the Cosmic Microwave Background, the fluctuations of which are less than one part in one hundred thousand.

The most accepted view today is that all the structure we observe today was formed as a consequence of the growth of primordial fluctuations.

The primordial fluctuations caused gas to be attracted to areas of denser material, and star clusters and stars.

One consequence of this model is that the location of galaxies indicates areas of higher density of the early universe.

Hence the distribution of galaxies is closely related to the physics of the early universe..

Recent discoveries

The first stars in our universe are long gone, but their light still shines, giving us a peek at what the universe looked like in its early years.




Astrophysicists believe they've spotted a faint glow from stars born at the beginning of time. Harvey Moseley, Ph.D., an astrophysicist at the NASA Goddard Space Flight Center in Greenbelt, Maryland, says, "The reason they're faint is just because they're very, very far away, they're over at the far edge of the universe."



After the big bang, the universe stayed dark for about 200 million years. Now, new pictures reveal the first light from objects 13 billion light years away, the infants of our universe. "So, we're seeing what sometimes people call the first light in the universe, which formed after the big bang," Dr. Moseley explains.



Using pictures taken with the Spitzer Space Telescope, scientists first removed light from closer stars and galaxies. The light areas left in the background are believed to be the first objects in space. Alexander Kashlinsky, Ph.D., astrophysicist at the NASA Goddard Space Flight Center, says, "The early universe was a very hot place in this sense, like it was filled with objects that have been emitting light much more furiously than today."



Researchers say the objects are either stars, hundreds of times more massive than our own sun, or enormous black holes. Either way, the pictures bring us one step closer to learning how the universe was born. NASA's planned James Webb Space Telescope will be able to identify the nature of the newfound clusters and determine if they are stars or black holes.



BACKGROUND: Using a telescope as a time machine, scientists at NASA's Goddard Space Flight Center are closer to identifying the first objects of the universe. The latest observations from the Spitzer Space Telescope suggest that infrared light detected in a prior study comes from clusters of bright objects that lived within the first billion years after the Big Bang.



THE DARK AGE: According to current science, space, time and matter originated 13.7 billion years ago in a tremendous explosion called the Big Bang. A few hundred million years later, the first stars formed, ending the "dark age" of the universe. Astronomers believe the objects observed by the Spitzer telescope are either the first stars -- hundreds of times more massive than our sun -- or voracious black holes that are consuming gas and spilling out tons of energy. If they turn out to be stars, then the clusters might be the first mini-galaxies. Our own Milky Way was probably created when mini-galaxies like these merged.



IN THE INFRARED: The Spitzer scientists were looking specifically at the cosmic infrared background of the universe, a diffuse light from the early epoch when structure first emerged in the cosmos. A prior study reported in 2005 detected infrared light, suggesting that it originated from clumps of the very first objects in the universe. This second analysis indicates that this patchy light is scattered across the entire sky and comes from clusters of bright, monstrous objects more than 13 billion light-years away. Although that light began its journey as ultraviolet or visible light, by the time it reached earth, its wavelengths had been stretched into the infrared by the growing space-time that causes the universe's expansion. Based on the strength of the infrared light signal, they concluded that the total amount of energy produced by the objects was so large, only very large stars or black holes consuming a lot of matter would be capable of emitting it. Other parts of the cosmic infrared background are from distant starlight absorbed by dust and re-emitted as infrared light.



SEEING IS BELIEVING: When we peer into space with a telescope, we are actually looking back in time. Telescopes detect emitted light, and the light that reaches us from the closest galaxy, Andromeda, for instance, has taken two million years to reach us. The Spitzer telescope looked at the first brilliant objects to exist in our universe. The Spitzer telescope scanned five areas of the sky for about 25 hours per region, collecting light even from the faintest of objects. Then astronomers meticulously subtracted light from things that were in the way, such as foreground galaxies and dust in our solar system, or in interstellar clouds. When all that was left was the most ancient light, the scientists studied fluctuations in the intensity of the infrared brightness, revealing a clustering of objects to produce the observed light pattern.



The American Astronomical Society contributed to the information contained in the video portion of this report.

Intro

Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties (luminosity, density, temperature and chemical composition) of astronomical objects such as stars, galaxies, and the interstellar medium, as well as their interactions

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