Three billion years ago, Earth was a very different place.
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File Compression: New Tool for Life Detection?
Some of Earth’s oldest rocks contain intriguing layered structures. Were living organisms responsible, or was it merely a random chemical process? The answer, says one researcher, may be a simple matter of compressing a computer file.
March 31, 2003 • Posted by: Shige Abe • Report issue
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Lakeside Landing
NASA will soon launch two missions to Mars. Known, temporarily, as Mars Exploration Rover (MER) A and B, the two rovers will land in different regions of Mars to search for evidence of water in Mars’s past.
Scientists and engineers have whittled down an initial list of dozens of candidate landing sites to four finalists. Of these four, two are clear favorites among the scientists: Meridiani Planum and Gusev Crater. A previous article discussed Meridiani Planum; this article will focus on Gusev.
Gusev Crater is almost exactly halfway around the red planet from Meridiani Planum. While the latter site is ...
March 19, 2003 • Posted by: Yael Kovo • Report issue
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Solar Influence, Part II: Effects on and Near Earth
Before 1979, scientists didn’t have accurate data on the total amount of solar energy that reaches Earth. They were aware of the Sun’s fluctuations, but getting an accurate measurement of solar variation was difficult before the space age. In fact, it wasn’t until the launch of Nimbus-7 satellite in 1978 that a spacecraft was able to get accurate reading above the protective layer of Earth’s atmosphere.
Today scientists use the number 1,368 watts per square meter (W/m2) to denote the “solar constant.” This is an averaged value of solar energy emitted by the Sun ...
March 18, 2003 • Posted by: Shige Abe • Report issue
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Red Rovers: Returning to Mars
“Follow the water” is the mantra for NASA’s Mars exploration program. But present-day Mars is so cold, and its atmosphere so thin, that liquid water cannot exist on the planet’s surface.
What NASA can look for, though, is evidence that water was present and active on Mars in the distant past. There are strong indications, in images taken by cameras aboard orbiting spacecraft, that features of the Martian landscape have been carved by water. But some scientists argue that these features could have been caused by short-lived torrents of water – flash floods.
More interesting, because the ultimate goal ...
March 12, 2003 • Posted by: Yael Kovo • Report issue
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Solar Influence, Part I: Understanding Our Sun
Astrobiology is often concerned with mysteries of the past: Researchers vigorously pursue questions such as, “How did life on Earth originate,” “What was its course of evolution,” and “Did life originate elsewhere?” However, equally important are the questions that address the future. We are especially curious about Earth’s future, as well as humankind’s future off this planet. But to learn more about the prospects for our planet, we must understand the near and long term changes in Earth’s space environment.
This two part series will delve into the research involving our Sun, and how even slight energy ...
February 24, 2003 • Posted by: Shige Abe • Report issue
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Featured Question: A Few Thoughts on Mass Extinctions
These questions were submitted to our Ask An Astrobiologist website recently, and we’ve added images and video to this comprehensive answer.
February 19, 2003 • Posted by: Shige Abe • Report issue
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Rosetta Launch Cancelled
The European Space Agency (ESA) has announced the cancellation of their Rosetta mission launch. The mission was scheduled for launch at the end of January 2003, but due to persisting problems with the Ariane 5 rocket, the project has been postponed. The mission, named for the famous Rosetta stone, was originally intended to rendezvous with Comet Wirtanen in 2011. Because of its orbit, the Comet won’t be accessible again for another 170 years. Cancellation of this launch will place Rosetta into storage until another comet can be found. The mission may need to be redesigned in order to correctly target ...
February 07, 2003 • Posted by: Shige Abe • Report issue
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Exotic Earths
At the heart of astrobiology lie fundamental questions regarding the nature and prevalence of life. At the very minimum, life as we know it requires liquid water, a constant supply of energy, and specific elements to support its organic systems. But perhaps even more important than this laundry list of prerequisites, organisms require a home—a place that can constantly support and supply all that is necessary to keep them thriving in their environment.
Currently, Earth is the only place we know with unequivocal evidence for life; however, scientists have many good reasons to expect we will find life elsewhere ...
January 15, 2003 • Posted by: Shige Abe • Report issue
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From a River in Spain to a Crater on Mars
Interview with Andrew Knoll: Part I
In Pasadena Henry Bortman had the chance to talk with Andrew Knoll, a science team member for the Mars’ Exploration Rover missions and Fisher Professor of Natural History at Harvard University.
Astrobiology Magazine (AM): The first batch of images from Meridiani Planum, showing finely layered bedrock, have scientists pretty excited. What are your initial impressions?
Andrew Knoll (AK): We’ve known for several years, from orbital data, that there are layered rocks on Mars, but Opportunity gives us our first chance to actually go and work directly on some of these rocks in an outcrop ...
December 21, 2002 • Posted by: Yael Kovo • Report issue
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Life: Small but Robust
In the never-ending line of discoveries relating to the robustness of life, scientists have recently made two important discoveries. The first, which revived bacteria and algae that had been frozen for 2,800 years, is an exciting discovery for prospects of Mars life. Peter Doran of the University of Illinois at Chicago led a team to Lake Vida in the Antarctic. This is no ordinary lake; it has dozens of feet of ice above a pristine water body. They drilled through about 50 feet of ice and collected frozen samples, stopping just short of reaching the water layer. The team ...
December 20, 2002 • Posted by: Shige Abe • Report issue
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A Teacher in Space
NASA Administrator Sean O’Keefe announced recently that Barbara Morgan, the agency’s first Educator Astronaut, has been assigned as a crew member on a November 2003 Space Shuttle mission to the International Space Station.
December 17, 2002 • Posted by: Shige Abe • Report issue
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Mars Update
Mars astrobiology has recently received two almost simultaneous announcements on prospects of water on the Red Planet. The first, which deals with possibilities of a wet Mars in the past, was led by scientists at NASA Ames Research Center and the University of Colorado. This study challenges the notion that early Mars sustained a continuously warm environment that supported liquid water on its surface. Alternatively, this research shows that frequent impacts of large asteroids would have allowed only brief periods of a warm, wet environment. The impacts would cause extraordinary conditions that would induce massive floods, landslides, and quakes on ...
December 10, 2002 • Posted by: Shige Abe • Report issue
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Ripples in Time
Until the last fifteen percent of the Earth’s age, the continents were barren, lifeless wastelands. Life had yet to hit the shore. But a kind of molecular clock says the hands of time may have started ticking many billions of years earlier.
December 04, 2002 • Posted by: Shige Abe • Report issue
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Jupiter-Like Planets Formed in Hundreds – Not Millions – of Years, Study Shows
An accepted assumption in astrophysics holds that it takes more than 1 million years for gas giant planets such as Jupiter and Saturn to form from the cosmic debris circling a young star. But new research suggests such planets form in a dramatically shorter period, as little as a few hundred years.
November 28, 2002 • Posted by: Shige Abe • Report issue
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Focus on Titan
Conditions on Titan
Long hailed as a natural astrobiology laboratory, Saturn’s largest moon Titan is certainly on the minds of many scientists today. This moon is the second largest in the solar system (Jupiter’s Ganymede is the largest); its diameter is about 3200 miles (larger than the planet Mercury), or approximately the distance across the United States. Titan is interesting because it is unique: it is the only moon in the solar system known to have a thick atmosphere. The composition of the atmosphere is largely nitrogen (about 90%). By comparison, Earth’s atmosphere has a nitrogen content of about 78 ...
November 26, 2002 • Posted by: Shige Abe • Report issue