Uranus, Sunlight, and Seasons

http://www.news.wisc.edu/15776

"New Images Yield Clues to Seasons of Uranus"

The atmospheres of distant planets like Uranus were previously impossible to study in detail until improvements in imaging technology, optics, and the large ground-based telescope Keck II. Now researchers are able to study the seasonal changes that influence astonishing weather conditions. The study also examines how the sun influences the planet's weather.

The study was conducted by Sromovsky and Pat Fry and William Ahue of UW-Madison, the study and Heidi B. Hammel of the Space Science Institute, Imke de Pater of UC-Berkeley, Kathy Rages and Mark Showalter of the SETI Institute, and Marcos van Dam of the Keck Observatory.

Sromovsky says the study is challenging because the seasons change so slowly and Uranus is so far away. Uranus has huge changes in the distribution of solar heating due to the extreme tilt, an unusually large 98 degrees from its orbit plane. During a year the poles of the planet get more sunlight that the equator. Seasons change so infrequently because Uranus has an 84 year orbit.

However, in 2007 Uranus reached its equinox, when the sun is directly over the equator and the little sunlight the planet gets is distributed evenly over the northern and summer hemispheres. The last time this happened scientists didn't have the technology to see any features of the planet, so this time gave scientists their best opportunity to study the seasonal dynamics of Uranus.

Uranus has a blue-green atmosphere of hydrogen, helium and methane and has a ring system. It also has some of the strangest cloud features in the outer solar system. Because the planet lacks a measurable internal heat source and the sun's warmth is 400 times less than it is at the Earth, parts of Uranus can reach below 360 degrees fahrenheit. This is why "Although both hemispheres were symmetrically heated by sunlight at equinox, the atmosphere itself was not symmetric, implying that it was responding to past sunlight instead if current sunlight, a result of Uranus's cold atmosphere and long response time," explains Sromovsky.

The most recent Keck II images show changes in the brightness of cloud bands in the planet's northern and southern hemispheres. Also, there are changes in the discrete cloud features; a massive vortex that had been oscillating in Uranus's southern hemisphere began drifting north and may soon dissipate. The new images showed Uranus' winds can achieve speeds of up to 560 miles per hour.

Some Interesting Exoplanets

In 1990 the first planets outside our solar system were discovered, and with the discovery of 51 pegasi b, the number of identified exosolar, or exoplanets, has soared to about 230. Some are stranger than others.

#10: The first exoplanet discovered is a hot jupiter also called Bellerphon after the constellation it's located in, known as 51 pegasi b.

#9: The closest exoplanet to our solar system is Epsilon Eridani b, orbiting a star only 10.5 ligh years from earth, orbits too far away to support liquid water. However, scientists predict there are other stars in the system that could support alien life.

#8: There are some planet-sized objects that have no sun at all and float untethered through space, called planemos. These are similar but smaller than brown dwarfs, which are failed stars too small to achieve stellar ignition.

#7: There are some exoplanets that orbit their parent stars so closely that their orbits last less than a day called ultra-short-period planets. One example is SWEEPS-10.

#6: One of the largest temperature differences astronomers have ever seen on an exoplanet occurs on Upsilon Andromeda b, which is tidally locked to its sun so one side of the planet is always facing its star. One side of the planet is hot as lava while the other is chilled below freezing.

#5: The youngest exoplanet discovered is less than one million years old and orbits Coku Tau 4, which is a star 420 light-years away.

#4: The oldest exoplanet discovered is 12.7 billion years old, more than 8 billion years before Earth and only 2 billion years after the Big Bang. The discovery of this planet raised the possibility that life began far sooner than scientists had imagined.

#3: The planet HD209458b has a year only 3.5 Earth-days long because the planet orbits so close to its star that at least 10 thousand tons of material is being blown away by stellar wind every second.

#2: One of the first planets to have its light analyzed, or sniffed, HD 189733b's atmosphere contains thick clouds of particles similar to grains of sand, but scientists suspect there might be water vapor hidden beneath the clouds.

#1: The smallest exoplanet ever detected is also the first to lie within the habitable zone of its parent star, raising the possibility that the surface might sustain liquid water and even life. It is called Gliese 581 C.

All in all, these exoplanets are remarkable discoveries that are slowly giving scientists more and more clues as to where to search for extraterrestrial life.

How William Borucki Launched the Kepler Mission

http://www.space.com/searchforlife/090625-seti-kepler-borucki.html

"The Exoplanet Sleuth Behind NASA's Kepler Mission"

Bill Borucki is the man behind NASA's decision to build and launch the first spacecraft capable of finding Earth-size planets orbiting other stars, Kepler. Of course Borucki was part of a team of scientists, computer scientists, engineers, and educators at the SETI Institute; however, he was the man steering the Kepler mission through navigating the maze of changing requirements, reallocated funding, technical issues, and political challenges.

Borucki grew up in Delevan, Wiscosin as a budding young scientist- he was president of the school's science club- and progressed from there. After earning both a B.S. and M.S. in physics, Borucki applied and earned his dream job at NASA. Then he worked at the Theoretical Studies Branch where they studied the atmospheres of Earth and other planets and built theoretical models of the atmosphere to understand how mankind's influence would change it. His interests emerged and he wrote two papers on his thinking about how photometry and spectrometry could be used to find other planets.

Finally, in 2000 he proposed a planet-finding mission to NASA, in response to a call for Discovery mission proposals, and the Kepler Mission was selected as the 10th Discovery Mission in December 2001. Although the mission encountered plenty of obstacles before finally launching, Bill Borucki and his team worked together to overcome them and successfully embark on a mission that could change our view of our world (and others) as we know it.

Some Strange Things in Space

http://www.space.com/bestimg/?guid=4499b37d6b914&cat=strangest

"Top 10 Strangest Things in Space"

There are many exceptionally astonishing things going on in the universe around us. One such phenomenon are quasars; bright beacons at the edge of the universe which release more energy than hundreds of galaxies combined. Scientists believe these are black holes in distant galaxies.

In space, although we tend to think empty space is simply empty, it is in fact countless 'virtual' subatomic particles that are constantly being created and destroyed. The short-lived particles fill the space with energy which creates an anti-gravitational force that pushes space apart.

Distortions in space-time predicted by Albert Einstein's theory of general relativity are known as gravity waves. These waves travel at the speed of light, but can only be detected by scientists when large cosmic events take place because otherwise they are too weak.

Discovered in space were strange particles that are opposite versions of particles making up normal matter, called anti-matter. For example, an electron has an anti-matter equivalent called a positron, which is opposite the electron by being positive. When normal and anti- matter meet their mass is converted into pure energy (E=mc2). Futuristic space ship designs incorporate anti-matter engines.

All in all, there are many strange things in space, some proven some not, that are slowly providing clues to the questions we pose as we seek for others like ourselves in the universe.

Switch to Digital TV Excludes Aliens from Viewing

http://www.space.com/searchforlife/090618-seti-aliens.html

"Aliens Lose in Switch to Digital TV"

Television signals as well as FM radio and radar have served as humans probing into deep space ever since World War II. A lot of people don't believe its possible for extraterrestrials to pick up on television, whether it be analog or digital, because the broadcasts would fade away long before they reached even the nearest star because every doubling of distance causes a four-fold reduction in intensity. But the massive switch to DTV has many others believing signals aliens used to be able to pick up will be replaced with smoother DTV. Radio technology is very sensitive though, and with large antennas it is possible to detect faint radio static from distant corners of the universe. Radio static from analog television is a lot of energy concentrated in a small range of frequencies which create spikes; aliens could find this emission and although they wouldn't have TV picture and sound they would know we were on the air.

However, DTV creates a smooth, low hiss, and television broadcast no longer emits a spike in frequencies that are detectable light-years away. On the other hand, the most powerful signals from our planet are radar transmissions such as the Arecibo telescope, which can be detected with a similarly sized antenna nearly one thousand light-years away. All in all, although its possible aliens will be cut off from being able to detect television broadcasts from earth, other frequencies will still be out there to catch their attention.

Tropical Storms on Saturn's Moon

http://www.space.com/scienceastronomy/090812-titan-clouds.html

"Tropical Storm Spotted on Saturn's Moon Titan"

Saturn's Moon Titan has a climate resembling that of Earth, but instead of a water cycle, Titan has a methane cycle. Clouds, rains and lakes all exist on Titan, but they are all made of methane. This is because the moon is so cold any water is frozen into rock-hard ice. Last summer, astronomers observed something very startling: a tropical storm.

This is not supposed to be there, according to the models that predicted that the equatorial region should be very dry and should not support cloud formation. While clouds of vaporized methane are not uncommon on Titan, though they have never before been observed in Titan's tropics. Scientists suspect the storm's trigger may have been some kind of geologic activity on the moon's surface, such as a geyser or new mountain range forming, or atmospheric effects.

This development simply furthers the fascination of Titan; the processes are nearly identical to Earth's, but with alien materials. As Saturn's 30-year-long orbit plays out a full rotation of seasons on the moon, scientists hope that by having telescopes trained on the moon and the every-six weekly view from NASA's Cassini spacecraft they will be able to learn a lot more.

New Equation for Habitable Planets&Primitive Life

Scientists have recently been attempting to come up with an equation to "quantify how suitable other planets are for life."

The equation is reminiscent of the Drake Equation, which judges the chances of contacting extraterrestrial civilizations., as it contains many variables that must be debated on.

The hard part is finding what variables are required, and which ones describe qualities of our Earth that aren't necessarily required to sustain intelligent life.
As a senior astronomer from SETI claims, "There's no definition of life that really works very well. Even if you were able to define life as we know it, you might be missing out on life as we don't know it."


The article ends with the message that its definitely very likely that we'll find primitive life on planets with at least semi-habitable atmospheres, the problem is figuring out what it takes to get from life to intelligent life.