Apod 3.6 Exceptional Rocket Waves Destroy Sun Dog

The Solar Dynamics Observatory, or SDO, designed to perpetually observe the sun, launched a few weeks ago. The blurry image of the rocket which carried SDO can be seen near the center of this image, surrounded by unexplained shock waves. There has been much debate over the origin of these ripples and the leading hypothesis is that they were caused by a sonic boom that occurred when the shuttle broke the sound barrier. Also to the right of the image is a sun dog. Sun dogs are extra images of the Sun caused by falling ice-crystals in the Earth's atmosphere. After the ripples had passed, the sun dog disappeared. When the waves hit the ice crystals, they were rearranged, thus destroying the sun dog. It is still under question why other rockets do not produce as noticeable shock waves.

Quarter 3 Biography Percival Lowell

Kenny Smith
Mr. Percival
Pd. 00
2/26/10
Percival Lowell
Percival Lowell was born on March 13th, 1855 in Boston, Massachusetts. He came from a family that produced many famous minds and personalities. He graduated from Harvard University in 1876. Before he decided to pursue a career in astronomy in 1893, he had served in many different fields, including foreign relations and affairs. In 1877, Italian astronomer Giovanni Schiaparelli had studied an opposition of Mars and he had found what looked like canals engraved into the Martian surface. These observations intrigued Percival Lowell and led him to start a career in astronomy.
Percival Lowell wanted to have the best viewing conditions possible for his observation of Mars at opposition. He wanted to see if Schiaparelli’s canals really did exist. Lowell conducted research and, with a hint from fellow astronomer W. H. Pickering, decided that Arizona would be the best place for his research. The site that he picked was just west of Flagstaff and was situated at an altitude of seven thousand plus feet. Lowell established the Lowell Observatory in this spot. From 1896-1897 he moved the observatory to a site in Mexico, but he soon realized that Arizona had a better viewing ability. Lowell was able to make what he believed to be clear observations of Mars, but his findings were eventually proven wrong. Percival Lowell’s decision to set up an observatory in an area of excellent seeing ability produced great results and inspired other astronomers to do the same. Nowadays, these types of observatories that are far from the light and smog of cities are by far the majority.
Lowell’s observations of Mars led him to formulate a hypothesis about intelligent life on the planet Mars. Percival Lowell believed that a civilization was trying to survive on a dying Mars. He believed that this alternative life form had built canals that went to the polar caps. Lowell presumed that these caps melted annually. Once the caps started to melt, the canals would fill with water and irrigate the crops that were keeping the civilization alive. Lowell observed dark spots on the Martian surface, which he credited to fertilized crops that he called “oases”. Lowell observed an ongoing darkening from poles to the equator as the seasons advanced from winter. This corresponded with his idea about vegetation and the release of water from the polar caps. Lowell started making drawings of the images he saw in his telescopes and released three books containing his findings. His work was highly criticized by his fellow astronomers but the public latched on to his ideas. Lowell’s ideas were largely discredited and were finally proved wrong when Mariner 4 took the first pictures of the Martian surface in 1965.
After his obsession with Mars, Lowell moved on to other planets. While studying Uranus, he discovered a discrepancy in Uranus’ orbit that is not fully accounted for by the pull of Neptune’s orbit. Therefore, Lowell deduced that a “Planet X” must exist beyond the orbit of Neptune. Lowell continually searched and photographed regions of the sky where he expected the new planet to be located. He died in 1916 before he could find the elusive planet. Then, in 1930, Clyde Tombaugh discovered the mysterious Planet X. This planet was named Pluto and its planetary symbol, a P with the base of an L, is meant to represent not only the first two letters of Pluto, but also Percival Lowell’s initials. Pluto was much fainter and smaller than expected because the discrepancy did not actually exist. The discrepancy was caused by a miscalculation of Neptune’s mass and affected the numbers Lowell used in his calculations.
Lowell also spent time making observations of the other planets in the Solar System, but compared to the time he spent looking for Pluto and observing Mars, these planets did not receive as much attention. Lowell was a daring astronomer who made bold predictions that could have shocked the world. Unfortunately for Lowell, most of his predictions were eventually discredited. If his predictions had come true and if he himself had discovered Pluto, Lowell would most likely be the most famous astronomer to have ever lived. His main legacy is in the realm of observing, for he was the first real pioneer of having good seeing to be able to make accurate observations.
Works Cited:
"Lowell, Percival." Complete Dictionary of Scientific Biography. Vol. 8. Detroit: Charles Scribner's Sons, 2008. 520-523. Gale Virtual Reference Library. Web. 25 Feb. 2010.
"Lowell, Percival (1855-1916)." The Worlds of David Darling. Web. 25 Feb. 2010. .
"Percival Lowell." Encyclopædia Britannica. 2010. Encyclopædia Britannica Online. 25 Feb. 2010 .
"Percival Lowell." Lowell Observatory. Web. 25 Feb. 2010. .

APOD 3.5 Cassini Spacecraft Crosses Saturn's Ring Plane

The Cassini Spacecraft that orbits Saturn has recently taken an image of Saturn's rings edge on. The rings seem to disappear in the image because their width is so small. The rings have a diameter of over 250,000 kilometers, but they are only one kilometer thick. The disappearance of the rings occurs on Earth every 15 years as the rings and our Earth are edge-on. This particular image was taken in February 2005 when the Cassini orbiter was in direct line with the rings. The image uses false colors so you can easily see the rings. In the rings, you can see small bumps that are actually small moons orbiting in the plane of the rings and some of them actually orbit inside of the rings. The shadow of the rings can be seen reflected on the "surface" of Saturn. These shadows can not be seen today due to Saturn's position in its orbit.

Astronomy Cast Ep. 108: The Life of the Sun

The sun formed 4.6 billion years ago. A giant cloud of gas and dust (nebula) started to contract and formed many young stars. The nebula was cold, which allowed it to collapse. If it was hot, it would not have been able to condense. The sun started out 10 times brighter than it is now. As the sun continued to contract it got fainter and fainter. At first, the sun was just a glowing ball of hydrogen and helium and eventually reached a time when it could start fusion. This is the protostar stage. In the life of the sun, it represents a very small chunk. The sun then settled into a main-sequence star, which it is now. When the Sun first became main-sequence, it was a little hotter than it is now, but it has been mostly constant. Slowly, the sun is starting to get warmer and warmer (over millions of years). Currently, the sun appears to be in a slight cooling stage. The sun will most likely stay main-sequence for another 5 billion years. The Earth is about half way through its life right now. When the sun nears the end of its life, it will get hotter and will evaporate the oceans. In about 5 billion years, the sun will start to run out of hydrogen for fusion and will start to contract. Once the sun collapses, a shell of hydrogen surrounding a helium core will ignite. This phase is the red giant phase. As the sun continues to collapse, pressure from the weight of the material causes the core temperature to continue to rise. Once the core temperature reaches 10^8 degrees, the helium core ignites, otherwise known as a helium flash. The Sun is now a Horizontal Branch Star or the sub-giant phase. The sun now begins to bloat and drop in luminosity. Eventually, all the helium runs out. The star collapses and forms a carbon-cored star surrounded by a shell of burning hydrogen and helium. The Sun is now AGAIN a red giant. The sun could also become a variable star, where the sun pulsates and has a variable luminosity. If the sun does become a variable star, it would be a Mira variable. The sun's atmosphere now reaches to the orbit of Earth. Some of the outer layers are so far away that they can actually be released into space. The sun is now only 4,000 K and the star is red, but the star is so much larger that it has a larger luminosity. The sun spends almost all of its life as main-sequence, and the other stages occur over a combined couple hundred millions of years. When the Sun starts to expel its atmosphere, a planetary nebula will form. The sun starts to run out of energy. All hydrogen and helium burning stop and the atmosphere drift away. The Sun enters the Degenerate Gas Phase, where the helium and hydrogen are packed into a sphere, forming a white dwarf. Although no fusion is occurring, the Sun is still hot. It is releasing heat as it cools to oblivion. The planetary nebula blends in with the surrounding interstellar medium and the dwarf cools to the temperature of space. The sun is now a black dwarf or cold white dwarf. As the sun loses mass, the planets' orbits will expand and the Earth will actually survive the changing phases.

I was amazed by the life our Sun will endure in the future. The constant changing that will occur over such a short period of time after a long life of little variability is truly amazing. It would truly be interesting to see the sun change and see its impact on the surrounding planets. I've learned a lot from this podcast that I previously did not have a clue about and the evolution of stars is incredible.

Astronomy Cast Ep. 160- Eclipses

Eclipses occur when one object passes between two objects in the line of sight and blocks the light given off by one object. Transits are when small things cross a larger but don't completely block all of the light. Occultation is when something in our solar system blocks the light from an object in another solar system. All are forms of eclipses. Eclipses don't happen every month because the moon's orbit is inclined. Solar Eclipses occur at new moon at certain times during the year. The moon is at the exact right distance to have full eclipses. Since the moon's orbit is elliptical, annular eclipses can occur because the moon's angular size is not large enough to completely block out the light of the sun. The changing distances between the moon, Earth, and Sun affect the kind of eclipse that occurs (annular or full). Hybrid eclipses are when some areas see annular eclipses, and some see full eclipses. You have to be in the shadow to see the solar eclipse, while anyone on Earth can see a lunar eclipse. Lunar eclipses occur during full moon. The light we see on the lunar surface during a lunar eclipse is caused by light being refracted by our atmosphere. Lunar eclipses can either occur in the lighter penumbra or darker umbra. Transits of Venus and Mercury can be seen across the sun, and transits of Jupiter's moons across Jupiter can also be seen (and other moon/planet systems). On Jupiter, these transits appear as solar eclipses. We can use transits to calculate the distance between the Earth, Venus and the Sun. This uses trigonometry be using the Earth's diameter as one side of a triangle, the distance as another, and the location of a planet on the sun's disk from different latitudes to create an angle. Pinhole cameras create an image of the eclipse on the ground. Use filters until totality, then you can watch the totality with the naked eye. A lunar eclipse requires no safety precautions. When extrasolar planets travel in front of a star, we can make measurements about the stars and planets because of the variability in light. Thus, we can discover Earth-like planets orbiting other stars.

Although I already knew most of the information presented in the telecast, it was very informative and i still learned a great deal about the workings of eclipses. Each minute was very informative to me as an astronomy student.

Apod 3.4 Night Launch of the Space Shuttle Endeavour

On February 8th at 4:14 A.M., the space shuttle Endeavor launched from Kennedy Space Center in Cape Canaveral, Florida. The mission is headed towards the International Space Station. The launch was originally scheduled for the night before, February 7th, but it was scrubbed minutes before its expected launch time. The mission will deliver the Tranquility module to the ISS. Tranquility will create more room for the astronauts in the ISS and has a large, circular window that will provide enhanced views of space. In this image, you can see large exhaust plumes billowing out of the bottom of the rockets. This night launch is the last night launch for the Space Shuttle program, which will end later on in this year. Only a few more daytime launches are left before the conclusion of this program.

Apod 3.3 P/2010 A2: Unusual Asteroid Tail Implies Powerful Collision

This unusual object was discovered in January by the ground-based LINEAR laboratory. Its unusual shape led to the Hubble Telescope's observation of the object last week. The object appears to be a comet due to its tail, but its 140 meter nucleus is off center, the tail does not appear to be composed of gas, and the structure around the nucleus is different than what normally appears in a comet. Scientists believe that the object formed from the collision of two small asteroids in the asteroid belt. The collision likely occurred at over 15,000 kilometers per hour and then pressure from the sun spread out the debris to form into a comet-like tail. Study of this comet is expected to help increase our understanding of the early solar system because it is believed that similar collisions occurred during the formation of the solar system.