APOD 2.5

12/01/2010 Martian Moon Phobos from Mars Express

Phobos is the larger of Mars's two moons. It is irregularly shaped, loaded with craters and resembles a potato. My theory is that a Russian astronaut from the ISS dropped his lunch during a spacewalk and it ended up orbiting Mars. It's unfortunate that the thick layer of dust covering Phobos precludes us from landing a probe on it, but if a human could ever reach Phobos, it would be a barrel of monkeys to wade through 3 feet of galactic dust on a giant potato. It took me a while to figure out why Phobos rises twice on certain parts of the planet. Near the equator, Phobos orbits so fast that it traverses the sky twice before a Martian day has elapsed. Closer to the poles, Phobos is not visible at all because it's beneath the horizon.

APOD 2.3

11/09/2010 NGC 4452: An Extremely Thin Galaxy

At first I thought this was a picture of a frisbee in space, but it turned out to be a view of galaxy NGC 4452 from the plane of the galaxy itself, which is even cooler! It is located in the Virgo Galaxy Cluster, which is the closest to the to the Milky Way. It is a lenticular galaxy, which is a disc galaxy that's used up most of its interstellar matter. It is roughly as thick as the Milky Way. The picture is almost perfectly edge-on with this galaxy. This would probably greatly surprise the average person who doesn't know much about astronomy, because they think it's all just stars and bright spots of light, whereas there are actually lots of interesting shapes like this line segment or molecular dust clouds.

APOD 2.2

10/30/2010 Ghost of the Cepheus Flame

This picture is very frightening. The molecular dust cloud kind of looks like a seahorse. The constellation Cepheus contains several star forming regions. The Cepheus Flare is a star forming region of low and intermediate mass. The main nebula is the Ghost Nebula, whose brown color is caused by the stars behind it. The double stars are the beginnings of a binary star. It's fitting that they used a picture of the ghost nebula on the day before Halloween.

APOD 2.4

The 11/14/2010 picture is an artist's representation of the concept of the multiverse. Obviously one cannot take a picture of an alternate universe, as with most astronomical phenomena, so the picture is really just a chance for the artist to doodle some circles and neat colors and call it a multiverse. Essentially, the multiverse is the collection of universes. Many scientists don't even agree that there are other universes, but they are hypothesized to explain where matter goes when it falls into a black hole, for example. It is very tantalizing to ponder what life is like for parallel analogues of myself in other universes. For instance, while I chose to eat a peanut-butter and jelly sandwich for lunch today, my parallel twin might have eaten a Caesar salad. Scientists are pondering other, less important issues pertaining to the multiverse, but there is virtually no way to empirically test them.

Observation 10/31/2010

Tonight at about 8:50, Sam Blumenstein and I saw a streak of light in the sky that might have been a meteorite. It was in the West, crossing the constellation Sagittarius and heading toward the horizon. It lasted for about 2 seconds, so it was extremely fortuitous that we happened to be looking in that direction. To say that we celebrated is an understatement.

APOD 2.1

10/25/10 Water Ice Detected Beneath Moon's Surface
This image shows the relative H2O content of the Moon, with blue areas containing ice below the surface and red areas dry. The thought of having people live for short intervals on the Moon is quite provocative, and having native supplies of water there would certainly make it easier. I don't understand why the scientists crashed LCROSS, a perfectly good satellite just to see if Cabeus crater contained any water, but perhaps they just had absolutely no use for the satellite anymore.

APOD 1.8

10/18/2010 It Came From The Sun

This image shows a powerful solar prominence. A prominence is a general term for a projection from the Sun, usually in the shape of a loop. The largest one recorded was 28 times the diameter of the Earth, and had a mass on the order of 10^11 tonnes! That's a lot of sandbags. I can't believe an object that seems so wispy contains so much matter. Prominences are held to the Sun by its magnetic field, and can be quiescent (long) or eruptive (short). I never knew about the solar cycle, a period of about 11 years between spurts of increased solar activity.