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Wednesday, July 13, 2011

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.

Tuesday, July 12, 2011

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.