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.

Galileo Galilei

Galileo Galilei

­ Galileo Galilei was an Italian scientist who played an instrumental role not only in the development of astronomy, but of modern science in general. He was born in Pisa in 1564 to Vincenzo Galilei, but at age 8 his family moved to Florence. He had three illegitimate children with Marina Gamba. He attended the University of Pisa and taught at the University of Padua. He died in 1642 and was buried in the Basilica of Santa Croce.

Galileo invented the horse-driven pump, the sector, the pendulum clock, and the thermoscope, a precursor to the modern thermometer.  However, his most important contribution was improving Hans Lippershey’s telescope. Lippershey is credited with inventing the telescope by lining up two convex lenses, but it only had a magnification of 3x. Galileo studied Lippershey’s schematic and built one with 30x magnification, which he sold to sailors and merchants. The telescope dramatically increased the empirical potential of astronomy; with it, the observer can see much more of the sky, but it also links the observation to an apparatus, which is much more consistent and trustworthy than the human brain.

Armed with the telescope, Galileo made numerous keen observations of the skies. For centuries, people had tried to explain away the spots on the Moon in a misguided attempt to preserve celestial perfection. Galileo observed that the amount of shading in these lunar spots varied with its angle to the Sun as if they were indentations. He thus discovered that the lunar surface has mountains and valleys, upending the expectation that celestial bodies had to be flawless. Galileo also proposed the concept of librations, which are slight movements of the Moon relative to the Earth that allow us to see it from different angles.

Galileo was the first person to definitively observe sunspots. Prior attempts dismissed the spots as a transit of Mercury. The major obstacle to overcome was being able to observe the sun without eye damage, which Galileo circumvented by observing the Sun through a telescope. He shared his observations of sunspots in 1911 but had a long feud with Christoph Scheiner over the explanation of the black spots. Scheiner claimed that there were objects with orbits very close to the Sun that were only visible at inferior conjunction. The debate was settled by David Fabricius, who showed that they were sunspots, not orbiting bodies.

Galileo was the first person to observe Jupiter’s four largest moons. He initially noticed what looked like 3 fixed stars in a line next to Jupiter, but after multiple sessions, it became clear that there were actually 4 objects and they were orbiting Jupiter. This discovery gave credence to the Copernican, heliocentric view: since Jupiter’s moons are not orbiting the Earth, Earth cannot be the center of all celestial motion.

Galileo was the first to observe the rings of Saturn. At first, he thought he was observing a tri-star formation, with two ancillary stars on either side of Saturn. However, he later observed that the lateral stars disappeared, a stymying realization. Not until 1858 did James Maxwell publish a mathematical analysis of these “stars” and show that they were rings made of many minuscule particles.

Galileo’s importance to the field of astronomy is inestimable. Modifying the telescope gave him the superior accuracy necessary to observe the rough lunar surface, sunspots, Jupiter’s moons, and Saturn’s rings.

Works Cited

1. "Galilei, Galileo (1564-1642)." World of Earth Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. Vol. 1. Detroit: Gale, 2003. 243-245. Gale Virtual Reference Library. Web. 1 Oct. 2010.

2. "Galileo Galilei." Wikipedia, the Free Encyclopedia. Web. 11 Oct. 2010. <http://en.wikipedia.org/wiki/Galileo_Galilei>.

3. Hightower, Paul. Galileo: Astronomer and Physicist. Springfield, NJ, USA: Enslow, 1997. Print.

4. "Science." The Galileo Project. Web. 11 Oct. 2010. <http://galileo.rice.edu/science.html>.