New 'Goldilocks' Planet

NASA's planet-hunting Kepler spacecraft has confirmed the discovery of its first alien world in its host star's habitable zone — that just-right range of distances that could allow liquid water to exist — and found more than 1,000 new explanet candidates, researchers announced today on December 5th.

The new finds bring the Kepler space telescope's total haul to 2,326 potential planets in its first 16 months of operation.These discoveries, if confirmed, would quadruple the current tally of worlds known to exist beyond our solar system, which recently topped 700. The potentially habitable alien world, a first for Kepler, orbits a star very much like our own sun. The discovery brings scientists one step closer to finding a planet like our own — one which could conceivably harbor life, scientists said. "We're getting closer and closer to discovering the so-called 'Goldilocks planet,'" Pete Worden, director of NASA's Ames Research Center in Moffett Field, Calif., said during a press conference today. [Gallery: The Strangest Alien Planets] The newfound planet in the habitable zone is called Kepler-22b. It is located about 600 light-years away, orbiting a sun-like star. Kepler-22b's radius is 2.4 times that of Earth, and the two planets have roughly similar temperatures. If the greenhouse effect operates there similarly to how it does on Earth, the average surface temperature on Kepler-22b would be 72 degrees Fahrenheit (22 degrees Celsius).

NASA Names Astrophysics Fellowship for Iconic Woman Astronomer

WASHINGTON, Aug. 30, 2011 /PRNewswire via COMTEX/ -- NASA has established an astrophysics technology fellowship named for the woman many credit as one of the key contributors in the creation of the Hubble Space Telescope. The Nancy Grace Roman Technology Fellowship in Astrophysics is designed to foster technologies that advance scientific investigations in the origin and physics of the universe and future exoplanet exploration. The fellowship will help early career researchers develop innovative technologies to enable scientific breakthroughs, while creating the skills necessary to lead astrophysics projects and future investigations. It also will foster and support early-career instrument builders on the path to long-term positions. "The Roman fellowship is an important opportunity to infuse new ideas and technologies into frontier research areas as diverse as dark energy, black holes and life elsewhere in the universe," said Jon Morse, astrophysics division director at NASA Headquarters in Washington. "This will be the most substantial fellowship at five years, compared to others that typically run two to three years." Beginning Nov. 18, early-career researchers may submit proposals for one-year concept studies for the development of new astrophysics technologies. Following a NASA review of the proposals, three to six applicants will be chosen for one-year fellowships to develop their concepts. Based on peer-review of the reports from the one-year studies, NASA will then select the fellows to implement the proposed technologies for up to four additional years. The first selection of fellows will be announced during February 2012. Finalists selected in early 2013 to execute their projects over four years will receive up to $1 million in funding. The fellowship's namesake is a distinguished American astronomer. Her celebrated career included multiple scientific and technical achievements at NASA and her important contributions to the design of the Hubble Space Telescope.

Space station flybys

The International Space Station (ISS) is making a series of bright flybys over Europe and North America this week. It outshines everything in the evening sky except the Moon. Sky watchers in the USA and Canada, check your cell phone for flyby times. Predictions are also available on the link below

A new way of looking at the sun

Aurora watch

April continues to be a good month for auroras. A new display could begin on April 20th when a solar wind stream is due to hit Earth's magnetic field. Wayne Barsky sends this dynamic preview from the Alaskan Arctic:

Near earth asteroids

Near Earth Asteroids

Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.

On September 16, 2011 there were 1218 potentially hazardous asteroids.

Recent & Upcoming Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2011 GP59
Apr 15
1.4 LD
--
58 m
2002 DB4
Apr 15
62.5 LD
--
2.2 km
2011 GJ3
Apr 27
7.7 LD
--
24 m
2008 UC202
Apr 27
8.9 LD
--
10 m
2009 UK20
May 2
8.6 LD
--
23 m
2008 FU6
May 5
75.5 LD
--
1.2 km
2003 YT1
May 5
65.3 LD
--
2.5 km
2002 JC
Jun 1
57.5 LD
--
1.6 km
2009 BD
Jun 2
0.9 LD
--
9 m
2002 JB9
Jun 11
71.5 LD
--
3.2 km
2001 VH75
Jun 12
42.2 LD
--
1.1 km
2004 LO2
Jun 15
9.9 LD
--
48 m
2001 QP181
Jul 2
35.1 LD
--
1.0 km
2011 GA55
Jul 6
64 LD
--
1.0 km
2011 EZ78
Jul 10
37.3 LD
--
1.5 km
2003 YS117
Jul 14
73.9 LD
--
1.0 km
2007 DD
Jul 23
9.3 LD
--
31 m

Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach.

Apollo 16

Apollo 16, the tenth manned mission in American Apollo space program, was the fifth mission to land on the Moon and the first to land in a highlands area. Launched on April 16, 1972, it was a J-class mission, featuring the program's second Lunar Roving Vehicle; and brought back 94.7 kg of lunar samples.
It included three lunar EVAs: 7.2 hours, 7.4 hours, 5.7 hours and one trans-earth EVA of 1.4 hours. Despite a malfunction in the Command Module which almost aborted the lunar landing, Apollo 16's lunar module landed successfully in the Descartes Highlands on April 21. Commander John W. Young and Lunar Module Pilot Charles Duke spent nearly three days on the lunar surface while Command Module Pilot Ken Mattingly orbited the Moon.
A subsatellite was released from the Service Module while in lunar orbit to carry out experiments on magnetic fields and solar particles (the first subsatellite had been released from Apollo 15).
The crew splashed down in the Pacific Ocean on April 27.

The original launch date in March 1971 was scrubbed well in advance due to an issue with a fuel tank supplying the RCS on the command module. The location of the problem forced a rolback to the VAB on January 27, 1971. The stack was returned after repairs well before the final countdown had initiated.[3]
A malfunction in a backup yaw gimbal servo loop in the main propulsion system of the CSM Casper caused concerns about firing the engine to adjust the CSM's lunar orbit, and nearly caused the Moon landing to be aborted. After a delayed first landing attempt, it was determined that the malfunction presented relatively little risk, and Young and Duke (who were already undocked, and flying LM Orion when the problem occurred) were permitted to land on the Moon.

Young and Duke spent three days exploring the Descartes highland region, while Mattingly circled overhead in Casper. This was the only one of the six Apollo landings to target the lunar highlands. On the first day of lunar surface operations, news was relayed to them that the House of Representatives had approved the Space Shuttle program. Young stated that it was needed.[4]
The astronauts discovered that what was thought to have been a region of volcanism was actually a region full of impact-formed rocks (breccias). Their collection of returned specimens included a 25-pound (11 kg) chunk that was the largest single rock returned by the Apollo astronauts[5] (nicknamed "Big Muley" after Bill Muehlberger, principal investigator for the mission's geology activities[6]). The scientific results of Apollo 16 caused planetary geologists to revise previous interpretations of the lunar highlands, concluding that meteorite impacts were the dominant agent in shaping the Moon's ancient surfaces.

Young and Duke set up their Apollo Lunar Surface Experiments Package (ALSEP), which included an experiment to measure heat flow between two probes they were to insert into holes drilled in the surface. Young, however, accidentally got one foot tangled up in the cable to one of the probes, detaching it and rendering the experiment useless.
The astronauts also conducted performance tests with the lunar rover, Young at one time getting up to a top speed of 11 miles per hour (18 kilometers per hour), which still stands as the record speed for any wheeled vehicle on the Moon (listed as such in the Guinness Book of Records).
Apollo 16 was originally scheduled for splashdown at 3:30 pm EST on April 28. The mission was shortened by a day (reducing the time in orbit around the Moon after the LM left the Moon and docked with the CSM) because of the problems with the command module prior to landing. As Duke described on the Apollo Lunar Surface Journal website: "The more you waited up there - if you did have a problem - the less time you had to think of something brilliant to fix it. They got a little nervous and brought us home a day early, I think, just to make sure we could have some ample time to fix any problems."[7] There were no problems encountered during the return flight.
The aircraft carrier USS Ticonderoga delivered the Apollo 16 command module to the North Island Naval Air Station, near San Diego, California on Friday, May 5, 1972. On Monday, May 8, 1972, ground service equipment being used to empty the residual toxic RCS fuel in the command module tanks, exploded in a Naval Air Station hanger. A total of 46 people were sent to the hospital for 24 to 48 hours observation, most suffering from inhalation of toxic fumes. Most seriously injured was a technician who suffered a fractured kneecap when the GSE cart overturned on him. A hole was blown in the NAS hangar roof 250 feet above, and about 40 windows in the hanger were shattered. The command module suffered a three-inch gash in one panel.[8][9][10]

Apollo 14

Apollo 14 was the eighth manned mission in the American Apollo program, and the third to land on the Moon. It was the last of the "H missions", targeted landings with two-day stays on the Moon with two lunar EVAs, or moonwalks.
Commander Alan Shepard, Command Module Pilot Stuart Roosa, and Lunar Module Pilot Edgar Mitchell launched on their nine-day mission on January 31, 1971 at 4:04:02 pm local time after a 40 minute, 2 second delay due to launch site weather restrictions, the first such delay in the Apollo program.[2] Shepard and Mitchell made their lunar landing on February 5 in the Fra Mauro formation; this had originally been the target of the aborted Apollo 13 mission. During the two lunar EVAs, 42 kilograms (93 lb) of Moon rocks were collected and several surface experiments, including seismic studies, were performed. Shepard famously hit two golf balls on the lunar surface with a make-shift club he had brought from Earth. Shepard and Mitchell spent about 33 hours on the Moon, with about 9½ hours on EVA.
While Shepard and Mitchell were on the surface, Roosa remained in lunar orbit aboard the Command/Service Module, performing scientific experiments and photographing the Moon. He took several hundred seeds on the mission, many of which were germinated on return resulting in the so-called Moon trees. Shepard, Roosa, and Mitchell landed in the Pacific Ocean on February 9.

Apollo 15

Apollo 15 was the ninth manned mission in the American Apollo space program, the fourth to land on the Moon and the eighth successful manned mission. It was the first of what were termed "J missions", long duration stays on the Moon with a greater focus on science than had been possible on previous missions. It was also the first mission where the Lunar Roving Vehicle was used.
The mission began on July 26, 1971, and concluded on August 7. At the time, NASA called it the most successful manned flight ever achieved.[2]
Commander David Scott and Lunar Module Pilot James Irwin spent three days on the Moon and a total of 18½ hours outside the spacecraft on lunar extra-vehicular activity. The mission was the first not to land in a lunar mare, instead landing near Hadley rille in an area of the Mare Imbrium called Palus Putredinus (Marsh of Decay). The crew explored the area using the first Lunar Rover, allowing them to travel much farther from the Lunar Module lander than had previously been possible. They collected a total of 77 kg (170 lbs) of lunar surface material. At the same time, Command Module Pilot Alfred Worden orbited the Moon, using a Scientific Instrument Module (SIM) in the Service Module to study the lunar surface and environment in great detail with a panoramic camera, gamma ray spectrometer, mapping camera, laser altimeter, mass spectrometer, and lunar sub-satellite deployed at the end of Apollo 15's stay in lunar orbit (an Apollo program first).
Although the mission accomplished its objectives, their success was somewhat overshadowed by bad publicity that accompanied public awareness of the unauthorized souvenirs carried aboard by the astronauts, who had made plans to sell those souvenirs upon their return.

Apollo 13

Apollo 13 was the seventh manned mission in the American Apollo space program and the third intended to land on the Moon. The craft was launched on April 11, 1970, at 13:13 CST. The landing was aborted after an oxygen tank exploded two days later, crippling the service module upon which the Command Module depended. Despite great hardship caused by limited power, loss of cabin heat, shortage of potable water and the critical need to jury-rig the carbon dioxide removal system, the crew returned safely to Earth on April 17.
The flight was commanded by James A. Lovell with John L. "Jack" Swigert as Command Module pilot and Fred W. Haise as Lunar Module pilot. Swigert was a late replacement for the original CM pilot Ken Mattingly, who was grounded by the flight surgeon after exposure to German measles.

Objective
The Apollo 13 mission was to explore the Fra Mauro formation, or Fra Mauro highlands, named after the 80-kilometer-diameter Fra Mauro crater located within it. It is a widespread, hilly geological (or selenological) area thought to be composed of ejecta from the impact that formed Mare Imbrium.
The next Apollo mission, Apollo 14, eventually made a successful flight to Fra Mauro.

Oxygen tank incident

Explosion

"Houston, we've had a problem."

Swigert and Lovell reporting the incident on April 14, 1970
Problems listening to this file? See media help.
En route to the Moon, approximately 200,000 miles (320,000 km) from Earth, Mission Control asked the crew to turn on the hydrogen and oxygen tank stirring fans, which were designed to destratify the cryogenic contents and increase the accuracy of their quantity readings. Approximately 93 seconds later the astronauts heard a loud "bang", accompanied by fluctuations in electrical power and firing of the attitude control thrusters.[6] The crew initially thought that a meteoroid might have struck the Lunar Module (LM).
In fact, the number 2 oxygen tank, one of two in the Service Module (SM), had exploded.[10] Damaged Teflon insulation on the wires to the stirring fan inside oxygen tank 2 allowed the wires to short-circuit and ignite this insulation. The resulting fire rapidly increased pressure beyond its 1,000 pounds per square inch (6.9 MPa) limit and the tank dome failed, filling the fuel cell bay (Sector 4) with rapidly expanding gaseous oxygen and combustion products. It is also possible some combustion occurred of the Mylar/Kapton thermal insulation material used to line the oxygen shelf compartment in this bay.[11]


Apollo 13's damaged Service Module, as photographed from the Command Module after being jettisoned
The resulting pressure inside the compartment popped the bolts attaching the Sector 4 outer aluminum skin panel, which as it blew off probably caused minor damage to the nearby high-gain S-band antenna used for translunar communications. Communications and telemetry to Earth were lost for 1.8 seconds, until the system automatically corrected by switching the antenna from narrow-band to wide-band mode.
Mechanical shock forced the oxygen valves closed on the number 1 and number 3 fuel cells, which left them operating for only about three minutes on the oxygen in the feed lines. The shock also either partially ruptured a line from the number 1 oxygen tank, or caused its check or relief valve to leak, causing its contents to leak out into space over the next 130 minutes, entirely depleting the SM's oxygen supply.[11]
Because the fuel cells combined hydrogen and oxygen to generate electricity and water, the remaining fuel cell number 2 finally shut down and left the Command Module (CM) on limited-duration battery power. The crew was forced to shut down the CM completely and to use the LM as a "lifeboat".[12] This had been suggested during an earlier training simulation but had not been considered a likely scenario.[13] Without the LM, the accident would certainly have been fatal [14].

Apollo 11

Apollo 11 was the spaceflight which landed the first humans, Neil Armstrong and Edwin "Buzz" Aldrin, Jr, on Earth's Moon on July 20, 1969, at 20:17:39 UTC. The United States mission is considered the major accomplishment in the history of space exploration.
Launched from the Kennedy Space Center Launch Complex 39 in Merritt Island, Florida on July 16, Apollo 11 was the fifth manned mission, and the third lunar mission, of NASA's Apollo program. The crew consisted of Armstrong as Commander and Aldrin as Lunar Module Pilot, with Command Module Pilot Michael Collins. Armstrong and Aldrin landed in the Sea of Tranquillity and became the first humans to walk on the Moon on July 21. Their Lunar Module, Eagle, spent 21 hours 31 minutes on the lunar surface, while Collins remained in orbit in the Command/Service Module, Columbia.[2] The three astronauts returned to Earth on July 24, landing in the Pacific Ocean. They brought back 47.5 pounds (21.5 kg) of lunar rocks.
Apollo 11 fulfilled U.S. President John F. Kennedy's goal of reaching the Moon before the Soviet Union by the end of the 1960s, which he had expressed during a 1961 mission statement before the United States Congress: "I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to the Earth."[3]
Five additional Apollo missions landed on the Moon between 1969 and 1972.

Hubble's Neptune Anniversary Pictures

Today, Neptune has arrived at the same location in space where it was discovered nearly 165 years ago. To commemorate the event, NASA's Hubble Space Telescope has taken these "anniversary pictures" of the blue-green giant planet.

Neptune is the most distant major planet in our solar system. German astronomer Johann Galle discovered the planet on September 23, 1846. At the time, the discovery doubled the size of the known solar system. The planet is 2.8 billion miles (4.5 billion kilometers) from the Sun, 30 times farther than Earth. Under the Sun's weak pull at that distance, Neptune plods along in its huge orbit, slowly completing one revolution approximately every 165 years.
These four Hubble images of Neptune were taken with the Wide Field Camera 3 on June 25-26, during the planet's 16-hour rotation. The snapshots were taken at roughly four-hour intervals, offering a full view of the planet. The images reveal high-altitude clouds in the northern and southern hemispheres. The clouds are composed of methane ice crystals.
The giant planet experiences seasons just as Earth does, because it is tilted 29 degrees, similar to Earth's 23-degree-tilt. Instead of lasting a few months, each of Neptune's seasons continues for about 40 years.
The snapshots show that Neptune has more clouds than a few years ago, when most of the clouds were in the southern hemisphere. These Hubble views reveal that the cloud activity is shifting to the northern hemisphere. It is early summer in the southern hemisphere and winter in the northern hemisphere.
In the Hubble images, absorption of red light by methane in Neptune's atmosphere gives the planet its distinctive aqua color. The clouds are tinted pink because they are reflecting near-infrared light.
A faint, dark band near the bottom of the southern hemisphere is probably caused by a decrease in the hazes in the atmosphere that scatter blue light. The band was imaged by NASA's Voyager 2 spacecraft in 1989, and may be tied to circumpolar circulation created by high-velocity winds in that region.
The temperature difference between Neptune's strong internal heat source and its frigid cloud tops, about minus 260 degrees Fahrenheit, might trigger instabilities in the atmosphere that drive large-scale weather changes.
Neptune has an intriguing history. It was Uranus that led astronomers to Neptune. Uranus, the seventh planet from the Sun, is Neptune's inner neighbor. British astronomer Sir William Herschel and his sister Caroline found Uranus in 1781, 55 years before Neptune was spotted. Shortly after the discovery, Herschel noticed that the orbit of Uranus did not match the predictions of Newton's theory of gravity. Studying Uranus in 1821, French astronomer Alexis Bouvard speculated that another planet was tugging on the giant planet, altering its motion.
Twenty years later, Urbain Le Verrier of France and John Couch Adams of England, who were mathematicians and astronomers, independently predicted the location of the mystery planet by measuring how the gravity of a hypothetical unseen object could affect Uranus's path. Le Verrier sent a note describing his predicted location of the new planet to the German astronomer Johann Gottfried Galle at the Berlin Observatory. Over the course of two nights in 1846, Galle found and identified Neptune as a planet, less than a degree from Le Verrier's predicted position. The discovery was hailed as a major success for Newton's theory of gravity and the understanding of the universe.
Galle was not the first to see Neptune. In December 1612, while observing Jupiter and its moons with his handmade telescope, astronomer Galileo Galilei recorded Neptune in his notebook, but as a star. More than a month later, in January 1613, he noted that the "star" appeared to have moved relative to other stars. But Galileo never identified Neptune as a planet, and apparently did not follow up those observations, so he failed to be credited with the discovery.
Neptune is not visible to the naked eye, but may be seen in binoculars or a small telescope. It can be found in the constellation Aquarius, close to the boundary with Capricorn.
Neptune-mass planets orbiting other stars may be common in our Milky Way galaxy. NASA's Kepler mission, launched in 2009 to hut for Earth-size planets is finding increasingly smaller extrasolar planets including many the size of neptune.

Einstein Rings

In observational astronomy an Einstein ring is the deformation of the light from a source (such as a galaxy or star) into a ring through gravitational lensing of the source's light by an object with an extremely large mass (such as another galaxy, or a black hole). This occurs when the source, lens and observer are all aligned. The first complete Einstein ring, designated B1938+666, was discovered by collaboration between astronomers at the University of Manchester and NASA's Hubble Space Telescope in 1998.[1]

Einstein's riddle

This is the story behind Einstein's riddle: Albert Einstein supposedly created it in the late 1800s, and it is also said that he claimed 98% of the world population couldn't find a solution. In reality, it isn't that difficult, and I am not sure of the true origin, but I have seen this one floating around the internet, and it is a good brain exercise, so here it is:
- In a street there are five houses, painted five different colors.

- In each house lives a person of different nationality.

- These five homeowners each drink a different kind of beverage, smoke different brand of cigar and keep a different pet.

Einstein's riddle is: Who owns the fish?

Necessary clues:

1. The British man lives in a red house.
2. The Swedish man keeps dogs as pets.
3. The Danish man drinks tea.
4. The Green house is next to, and on the left of the White house.
5. The owner of the Green house drinks coffee.
6. The person who smokes Pall Mall rears birds.
7. The owner of the Yellow house smokes Dunhill.
8. The man living in the center house drinks milk.
9. The Norwegian lives in the first house.
10. The man who smokes Blends lives next to the one who keeps cats.
11. The man who keeps horses lives next to the man who smokes Dunhill.
12. The man who smokes Blue Master drinks beer.
13. The German smokes Prince.
14. The Norwegian lives next to the blue house.
15. The Blends smoker lives next to the one who drinks water.


The World's Hardest Riddle?

Some have claimed this to be the worlds hardest riddle. It isn't. It is a decent riddle, though, and a fun one for those who like riddles with systematic solutions. My own solution is below.

A chart seems like the most useful tool to help solve this riddle: Five columns for the five houses, and five rows for nationality, house color, type of drink, type of cigar, and finally, pets. Clue #8 states the man in the middle house drinks milk, so we can start by filling in that one of the 25 boxes created.

1st 2nd 3rd 4th 5th
Nation
Color
Drink Milk
Cigar
Pet

Then we deduce as much as possible from each clue as it becomes usable. The Norwegian living in the first house (# 9) could mean the first on the left or the right, since it isn't specified. I assume the left (first on chart) for now. Often, with riddles or puzzles, it is faster to make an assumption and if it doesn't work out go back and try the other way, rather than trying to hold open both possibilities while analyzing the other clues.

Clue# 14 says the Norwegian lives next to the blue house, so we can fill in the house color in the second column.

Clue # 4 says the green house is to the left of the white house, and #5 says it is occupied by a coffee drinker. The only place that works is in column four, so we can fill in color and drink there, and white for the color of the fifth.

Clue #1 says the British man is in the red house, and the third house is the only one that has neither color nor nationality specified yet, so we can fill in those two boxes. This also gives us the color of the first house, since only yellow is left. Yellow smokes Dunhill (#7), so we get that too.

Horses are next to the Dunhill smoker (#11). Put that in the second column and here we are so far:

1st 2nd 3rd 4th 5th
Nation Norwegian British
Color Yellow Blue Red Green White
Drink Milk Coffee
Cigar Dunhill
Pet Horses

I have to admit that I was stumped at this point, until I started looking for "clumps" of information. The idea is that if you can put three or more things together at this point, there is likely only one column they will fit in. In this case, I started with clue # 12: The man who smokes Blue Master drinks beer. That is two bits of information that go together.

Now we have to determine what other bit of information can be "attached" to that. From what we have on the chart, we can see that the Norwegian smokes Dunhill and the British man drinks milk, so we rule out two nationalities.# 13 says the German smokes Prince, and #3 says the Danish man drinks tea, so we are left with just the Swedish man, who we now know smokes Blue Master and drinks beer. Scanning the clues for more information about the Swedish man we see that he has dogs (# 2). The only place that these four items fit is column five, so we fill that in.

Now it gets a bit easier. The "Blends" smoker is next to a water-drinker (#15) and the cat owner (# 10), which fits only in house 2 now, so we can put "blends" in 2 and "water" in 1. That leaves only "tea" for 2. Clue # 3 says the Danish man drinks tea, so we get that as well, which leaves just one slot (house 4) for the German.

The German smokes Prince (#13), which leaves only one slot (house 3) for the Pall Malls. This is how the chart now looks:

1st 2nd 3rd 4th 5th
Nation Norwegian Danish British German Swedish
Color Yellow Blue Red Green White
Drink Water Tea Milk Coffee Beer
Cigar Dunhill Blends Pall Mall Prince Blue Master
Pet Horses Dogs

Clue # 6 says the person who smokes Pall Mall rears birds (house 3). Clue #10 says the man who smokes Blends lives next to the one who keeps cats, so "cats" can only fit in the house 1 column. That leaves but one slot open, so the coffee-drinking, Prince Cigar-smoking German in the green house owns the fish in Einstein's riddle.

This is my own way of figuring it out, and I am sure there are other ways to arrive at the answer. It is a fun puzzle, and particularly good for practicing logical reasoning. This makes it worthy of our time whether or not this is truly Einstein's riddle.

Hydrogen Peroxide found in Space

Molecules of hydrogen peroxide have been found for the first time in interstellar space. The discovery gives clues about the chemical link between two molecules critical for life: water and oxygen. On Earth, hydrogen peroxide plays a key role in the chemistry of water and ozone in our planet's atmosphere, and is familiar for its use as a disinfectant or to bleach hair blonde. Now it has been detected in space by astronomers using the European Southern Observatory-operated APEX telescope in Chile.

The Earth, the Sun and the Moon

The Earth, Sun, and Moon



The Earth

Earth, which is our base from which we look into space, is constantly moving. Understanding this movement is one of the most useful and important things in astronomy.

The earth orbits the sun in an elliptical orbit and the moon orbits the earth with the same kind of orbit. Looking down from the north pole, the earth spins in a counterclockwise direction on an imaginary line called its axis once every day. This accounts for the fact that the sun rises in the east and sets in the west. The earth’s axis is tilted with respect to the plane of its orbit at an angle of about 23.4 degrees. If we position ourselves high above the north pole, we would see that the earth orbits the sun in a counterclockwise motion, coming to the same position among the stars every 365.26 earth days. We would also see that the moon also orbits the earth in a counterclockwise motion. This is illustrated in the following example.


Figure 1: The directions of the orbits of the earth and moon.
The average distance from the earth to the sun, the semimajor axis of its orbit, is 149,597,890 km. This distance was not known until recently and it is called the astronomical unit or AU. The distances of the other planets to the sun are usually measured in astronomical units.

Because of the tilt of the earth, not every place on earth gets light every day. Also, some places have extremely short days.

As the earth revolves around the sun, the place where light shines the brightest changes. This motion gives us the different seasons. For instance, the poles receive less light than does the equator because of the angle that the land around the poles receive the sun’s light. When the north pole is tilted toward the sun, the northern hemisphere is presented to the sun at a greater angle than the southern hemisphere and the northern hemisphere gets warmer. When this happens, the northern hemisphere gets summer while the southern hemisphere gets winter. When the south pole is tilted toward the sun, the two seasons reverse hemispheres. This is illustrated in the following image.


Figure 2: The positions of earth at the different seasons. Counterclockwise from lower left: summer, fall, winter, spring (northern hemisphere).
The earth’s orbit is called the ecliptic. The plane which contains the ecliptic is the reference plane for the positions of most solar system bodies. Viewed from earth, the ecliptic is the apparent motion of the sun among the stars.

The earth’s equator is a circle going around the earth which is on a plane that is perpendicular to the earth’s axis. The equator and the plane on which it lies are illustrated in the following image.


Figure 3: The equatorial plane.
The Equinoxes

This equatorial plane is one of the most important in astronomy because it intersects the plane of the ecliptic and gives us a reference point in space by which we can measure the positions of stars. This plane also divides the earth into halves, the northern half being the northern hemisphere, the other half being the southern hemisphere. The intersection of these planes is a line, which for convenience we will call the line of equinoxes. The real definition of equinox is the point on the celestial sphere which intersects this line, but since the celestial sphere is an imaginary sphere with any size, the equinoxes are really lines. Also, for some purposes and illustrations, it is more convenient to think of the equinoxes as a line extending into space. For other purposes, it is convinient to think of the equinoxes as directions. The two planes are illustrated below.


Figure 4: The vernal equinox from two perspectives.
One half of this line is called the vernal equinox; the other half is called the autumnal equinox. At two points in the earth’s orbit this line intersects the sun. These two places mark the start of two of the four seasons, autumn or spring. The autumnal equinox starts autumn around September 23. From earth, this marks the time when the sun looks as if it is crossing the plane of the equator on its way south. The vernal equinox starts spring around March 21. This marks the time when the sun looks as if it is crossing the plane of the equator on its way north. The earth carries the plane of the equator along with it. When the sun looks as if it is on its way north or south, the earth is actually carrying the equatorial plane along so that it crosses the sun.

Perpendicular to this line of equinoxes is a line which contains the solstices. The solstices are points on the ecliptic which start the other two seasons, summer and winter, when they cross the sun. The summer solstice is one half of this line, the winter solstice is the other half of this line. The half of this line that is north of the celestial equator is the summer solstice, the half that is south of the celestial equator is the winter solstice. Currently, the winter solstice starts winter for the northern hemisphere at about the time the earth is closest to the sun. This line is illustrated in the following example.


Figure 5: The summer and winter solstices.
Because of centrifugal force involved when an object spins, the earth is not a perfect sphere, but is somewhat flattened at the poles and bulges out at the equator. The distance from any point on the equator to the center of the earth is longer than the distance from either pole to the center of the earth. This is illustrated in the following image which is exaggerated for clarity. The form caused by this equatorial bulge is called a geoid.


Figure 6: A geoid.
The Moon

The moon is the earth’s only natural satellite. Its average distance from the earth is 384,403 km. Its revolution period around the earth is the same length and direction as its rotation period, which results in the moon always keeping one side turned toward the earth and the other side turned away from the earth. This type of motion is called synchronous rotation. The side turned away from the earth is called the moon’s dark side, even though it is lit half of the time. The moon’s sidereal period of revolution is about 27.32 days long. This means that a line drawn through the center of the earth and the moon would point to the same star every 27.32 days. Due to slight variations in the orbital velocity of the moon, over a 30 year period, 59% of the moon’s surface is made visible. This is known as libration.

The moon’s orbit is not in the plane of the ecliptic and because of the elliptical nature of the moon’s orbit, it is not always the same distance from the earth. At the two intersections of the moon’s orbit and the plane of the ecliptic are two nodes. These nodes regress along the plane of the ecliptic, making one complete rotation every 18.61 years. See Orbits.

The Effect of the Moon

The moon has a noticeable effect on the earth in the form of tides, but it also affects the motion and orbit of the earth. The moon does not orbit the center of the earth, rather, they both revolve around the center of their masses called the barycenter. This is illustrated in the following animation.


Figure 7: The earth and moon revolving around the barycenter. Notice how the earth moves slightly.
The sun acts on the earth and its moon as one entity with its center at the barycenter. Since the earth revolves around the barycenter, which in turn orbits the sun, the earth follows a wobbly path around the sun. This is illustrated in the following example. To complicate things further, the barycenter is not always in the same place due to the elliptical nature of the moon’s orbit.


Figure 8: The wobble of the earth's orbit.
*Image illustrative only; number of intersections is greater.
The sun attracts the moon in such a way that it perturbs its orbit every 31.807 days, this phenomenon is called evection. The moon also changes the position of the earth’s equinoxes. The sun and moon each attract the earth’s equatorial bulge, trying to bring it into alignment with themselves. This torque is counteracted by the rotation of the earth. The combination of these two forces is a slow rotation of the earth’s axis, which in turn results in a slow westward rotation of the equinoxes. Looking down from the north pole, the equinoxes would appear to be rotating in a clockwise motion. The equinoxes and poles complete a rotation every 25,800 years. The equinoxes move at a rate of about 50.27 arc seconds per year. This phenomenon in known as the precession of the equinoxes and is illustrated in the following image.