Trackbacks
-
[...] Beyond Earth is not Mars, but a much more distant goal: the case for colonizing Saturn’s large moon, Titan. The authors correctly point out that the large moon has an atmosphere thick enough that bulky [...]
The Sky is Waiting.
Search AstroGuyz
Custom Search
Advertise on Astroguyz!
 |
|
 |
 |
Pictured is a Delta IV rocket launch from Cape Canaveral on November 21st, 2010. The image is a 20 second exposure taken at dusk, shot from about 100 miles west of the launch site. The launch placed a classified payload in orbit for the United States Air Force.
Difficult but not impossible to catch against the dawn or dusk sky, spotting an extreme crescent moon can be a challenge. The slender crescent pictured was shot 30 minutes before sunrise when the Moon was less than 20 hours away from New.� A true feat of visual athletics to catch, a good pair of binoculars or a well aimed wide field telescopic view can help with the hunt.
The Sun is our nearest star, and goes through an 11-year cycle of activity. This image was taken via a properly filtered telescope, and shows the Sun as it appeared during its last maximum peak in 2003. This was during solar cycle #23, a period during which the Sun hurled several large flares Earthward. The next solar cycle is due to peak around 2013-14.
Located in the belt of the constellation Orion, Messier 42, also known as the Orion Nebula is one of the finest deep sky objects in the northern hemisphere sky. Just visible as a faint smudge to the naked eye on a clear dark night, the Orion Nebula is a sure star party favorite, as it shows tendrils of gas contrasted with bright stars. M42 is a large stellar nursery, a star forming region about 1,000 light years distant.
Orbiting the planet in Low Earth Orbit (LEO) every 90 minutes, many people fail to realize that you can see the International Space Station (ISS) from most of the planet on a near-weekly basis. In fact, the ISS has been known to make up to four visible passes over the same location in one night. The image pictured is from the Fourth of July, 2011 and is a 20 second exposure of a bright ISS pass.
�
Next to the Sun, the two brightest objects in the sky are the Moon and the planet Venus. In fact, when Venus is favorably placed next to the Moon, it might just be possible to spot the two in the daytime. Another intriguing effect known as earthshine or ashen light is also seen in the image on the night side of the Moon; this is caused by sunlight reflected back off of the Earth towards our only satellite.
A mosaic of three images taken during the total lunar eclipse of December 21st, 2010. The eclipse occurred the same day as the winter solstice. The curve and size of the Earth�s shadow is apparent in the image.
08.06.10: Titan and the Case of the Missing Acetylene.
It started with two papers� as of late, much good and bad science journalism has been committed to the mysteries of Saturn�s largest moon, Titan. �A photochemical smog shrouded world, Titan is a dynamic place, and would easily qualify as a planet in its own right if it were in a solo orbit about the Sun. Titan has only begun giving up its secrets in the past decade; a close flyby of Voyager 1 in 1980 revealed an orange-brown disk devoid of detail. The arrival of the joint ESA-NASA Cassini Huygens mission has led to a wealth of data, as Cassini has performed a series of close mapping flybys of the moon and even deposited the successful Huygens probe on the surface in early 2005. Now, two papers from the Journal Icarus and the Journal of Astrophysical Research describe a curious anomaly; some process is consuming expected acetylene (HC2H) on the surface of Titan. Or something� but wait, let�s not got shouting, �Scientists find life on Titan!� We�re talking an indicator to a possible form of life. The studies site data gathered by Cassini�s infrared spectrometer and ion and neutral mass spectrometer as it swept by the moon. As a matter of fact, Cassini has just completed a 1,270 mile pass recently on June 5th. The process in question is the accumulation of hydrogen molecules high in the atmosphere and raining down to the lakes of methane and ethane coating the surface. �Evidence supports the idea that Titan should be coated with organic molecules, not to be confused with full fledged life itself (old school media take note!). Clearly, something is sequestering the expected acetylene that should be forming� could it be methane-based life? Keep in mind, Titan is a cold place; daytime temps reach a balmy -290 degrees Fahrenheit. Perhaps there may be warmer, as of yet undiscovered pockets of geological activity, but the very idea of methane based life is�very hypothetical. Such life forms would be vastly different than what we know here on Earth, and acetylene is on the short list of oxygen-metabolism substitutes. Mark Allen at NASA�s Astrobiology Institute points out that the lack of surface hydrogen and acetylene may have a non-biological cause; �Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed.� Other processes, such as bombardment by radiation or cosmic rays (remember Titan doesn�t have an ozone layer) or the chemical�action of minerals could play a role.
So, what should the man on the street take away from this? That Titan is a fascinating and dynamic place, a place in our solar system where things are happening. Clearly, there is more to Titan�s methane- fueled hydrologic cycle than we currently understand, and a spacecraft such as the proposed Titan Survey mission that would put a dirigible-based probe in the atmosphere would go a long way towards solving the �Life on Titan� puzzle. For now, it�ll just have to go on our �Mars-Europa� short-list of interesting places to visit� but don�t believe the �Aliens found on Titan!� news hype just yet!