Archive for August, 2008

Our Next Giant Leap

Saturday, August 30th, 2008 by Evan Finnes

One-fifth of the entire world population watched the live broadcast of the first Moon-walk, so it is no surprise that we all remember or have heard those famous words spoken by Neil Armstrong in 1969. The Apollo program and lunar landings aided the advancement of many fields of engineering, and is considered by many to be the greatest achievement of mankind. Nearly forty years after the end of the Apollo missions, NASA finally plans on returning to the Moon.

Before NASA returns man to the Moon, they plan on doing extensive studies. The first mission to the Moon will be the Lunar Reconnaissance Orbiter (“LRO”), which is scheduled to launch by the end of this year or early next year. The LRO will be equipped with the most sophisticated technology ever sent to the Moon–including instruments to make detailed 3-D maps of the entire lunar surface, locate subsurface water-ice, and record radiation levels to help develop technologies which will ensure the safety of future crews.

Launching with the LRO is the Lunar Crater Observation and Sensing Satellite (“LCROSS”). In 1999, NASA’s Lunar Prospector detected the spectral signature of hydrogen in the Moon’s permanently shadowed polar craters. LCROSS will impact the Moon in one of these craters. The impact will send a plume of material into space, which will be observed by a near-infrared camera, which will analyze the plume for traces of water. Presence of water on the Moon would be an important natural resource for a future lunar colony.

NASA plans on having mankind back on the Moon by 2020. Utilizing the new equipment which is currently being developed as part of the Constellation program, four astronauts will land on the Moon aboard the new Altair Lunar Lander, which will provide life support for the initial week long mission to the Moon. The Lunar Lander will be launched into low-Earth orbit aboard an Ares V Rocket, where it will rendezvous with the Orion crew vehicle.

Returning man to the Moon is the important first step in NASA’s new Moon Mars and beyond initiative proposed by George Bush. The Lunar surface will be explored and studied in an attempt to learn how to build a successful space colony. Risks such as radiation and psychological trauma will have to be fully understood and overcome before any long-term manned missions to Mars, or elsewhere, can be pursued. Having a colony on the Moon will also help us study how the Earth and Moon were formed, and giant telescopes on the Moon will not have the atmospheric interference which is a problem on Earth. Along with the many scientific advances which will follow future lunar landings, returning to the Moon will renew the general population’s interest in space exploration.

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Bigger, Brighter, and More Numerous

Friday, August 29th, 2008 by Bellatrix

Edmond Halley first discovered the star Eta Carinae in 1677. At first it wasn’t that special, it was a magnitude 4 star located in the Carina constellation in the Southern Hemisphere. However, people started to take notice when it kept changing its brightness. First, getting dimmer but then brightening and it has continued to brighten for several hundred years. Nowadays it is known as the brightest star in our galaxy. It has a mass more than 100 times the mass of the sun and is more than three million times brighter. Eta Carinae was thought to be at the limit of how large and how luminous a star can be; well there’s a new star giving Eta Carinae a run for its money.

A star nicknamed the “Peony Nebula Star” may be the new reigning champ for the title of brightest star in the galaxy. It has so far been estimated at 3.7 million times as bright as the sun, or 3.7 million solar luminosities. However, the mass seems to beat Eta Carinae, weighing in at 150 to 200 solar masses. Now this isn’t a newly discovered star, we’ve known that this star existed for some time, but had no idea about its astounding qualities. Peony is buried deep in the galaxy center where it was obscured from our telescopic eyes by gas, dust, and other types of interstellar medium. It was only recently with the help of the NASA Spitzer space telescope that we were able to peer through all of that and see the true star that lied beyond it all.

Spitzer was able to accomplish this because it is an infrared telescope and because it is a space telescope. Peony’s optical light is absorbed in all the interstellar gas and dust so we are not able to see it well on earth, but we would be able to see it’s infrared light. However, Earth’s atmosphere absorbs a very large majority of infrared radiation that comes to us, thus ground based telescopes are not able to see the infrared light from Peony. Spitzer solves these problems by being both above the atmosphere and an infrared telescope.

People first thought that stars like Eta Carinae were rare. This is because of something called the Eddington Limit. The Eddington Limit is a theoretical limit on the size and luminosity of a star, saying that if a star is much larger than about 100 solar masses the outward pressure of the radiation literally blows the star apart. And we now know that Eta Carinae is actually blowing itself apart. But now we may have to question how rare these stars really are and what the size limit really might be. As Spitzer continues to probe the center of the galaxy, where more of these monsters are thought to be hiding, we may have to change what we thought we knew about these massive fireballs.

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Null Cosmology and Supermassive Black Holes

Thursday, August 28th, 2008 by William Reynolds

Ahhh, tis Thursday and time for another installment of Schopenhauer Was Right. However, in its stead I want to very briefly address an epistemological concern I’ve been chewing on lately:  The abandoned treatment of essential purpose(s) in scientific method manifest in the treatment of supermassive black holes.

For the record, I must distinguish what I mean by essential purpose.  For example, it may be rightfully said that supermassive black holes cause the formation of spiral galaxies.  If may also be said that spiral galaxies cause the formation of supermassive black holes.  Neither of these statements address the essential purposes of supermassive black holes as vital constituents of spiral galaxies.  To be essential is to be purposeful – to be vital to the constitution of an existing whole.

In his book, Our Undiscovered Universe: Introducing Null Physics, Terence Witt outlines a cosmology based on his theory Null physics. His Null cosmology accounts for the purposes of supermassive black holes observed at the center of spiral galaxies. Indeed, by asking the question “Why are supermassive black holes at the center of spiral galaxies”, Mr. Witt reminds all of us that the universe is not superfluous in essence or purpose. Are there nonessential physical laws? Are there excesses of gravitational forces or electromagnetic currents upsetting the balance of our universe?

Terence Witt represents the general will of a number of thinkers who remain unsatisfied with the direction science has chosen in forsaking the essential purposes of things in order simply describe what things do and what they may do. We are reasonably confident in our understanding of black holes i.e. how they interact with matter and light. Additionally, we must similarly seek to understand the essential purpose of supermassive black holes. Or are we to believe supermassive black holes have no purpose in relation to the stellar and planetary swirl of a spiral galaxy?

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Wednesday, August 27th, 2008 by Evan Finnes

Saturn’s sixth largest moon, Enceladus, was discovered in 1789 by British Astronomer William Herschel. With a low albedo and close proximity to Saturn, Enceladus is difficult to observe. Because of this difficulty little was known about this moon until the Voyager flybys in the 1980’s. Voyager 1 discovered that Enceladus is located in the densest part of Saturn’s E Ring, and Voyager 2 discovered that Enceladus has diverse and relatively complicated surface features.

The Voyager missions generated a number of questions about the small moon: “Is there a connection between Enceladus and Saturn’s E-ring?” “What is causing the tectonic activity which is deforming Enceladus’s surface?” The recent Cassini mission was able to answer these questions, along with generation new discoveries and new questions.

To answer the first question, Cassini discovered that Enceladus is the fourth known body in the solar system with active volcanism. The other three are Earth, Jupiter’s moon Io, and Neptune’s moon Triton. This volcanism causes icy jets, plumes of water vapor, and other materials to be shot into the atmosphere. It is this cryovolcanism which was determined to be the cause of Saturn’s E Ring. Just recently Cassini photographed the volcanic southern pole. These pictures revealed a geological feature scientists are calling “tiger stripes”. These tiger stripes are 300 meter deep fractures and are surrounded by chunks of ice, and are the source of Enceladus’s volcanism.

Cassini also discovered the cause of the tectonic activity. Enceladus, like many other moons is traped in orbital resonances, this causes tidal heating on the moons interior. Like thought to exist on Jupiter’s moon Europa, this could also cause Enceladus to have a subsurface liquid ocean. Because of the volcanic activity a subsurface ocean on Enceladus is though to be only tens of meters beneath the surface, where the oceans on Europa are thought to be 100 kilometers beneath the surface.

Does Enceladus have a subsurface ocean? If it does, is this another place to look for signs of life? With many more Enceladus flybys to come, we may yet find out if there is a subsurface ocean, but we will certainly have to wait for the right mission if we want to determine if life exists.

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