A NASA developed rendering of HD 189733b, an extrasolar planet, is located more than 60 light years from Earth, which has the organic molecule methane in its atmosphere. Image Credit: NASA, ESA, and G. Bacon (STScI)
Hubble Discovers Life Basics On Distant Sphere
The upgraded Hubble telescope, with its perch circling above the Oblate Spheroid out in space, has discovered what is considered the basic evidence of the “signature” that life (as we understand it) could exist on another planet. The distant sphere is located 63 million light years away and is known as HD 189733b.
The process of the creation of life requires the existence of carbon based gasses and other chemicals on which bacteria and other life forms are composed. It is believed that without these signature compounds, life could and would not develop.
Stellar spectrography by a flame-cutting grid - Capella's Spectrum, order 1 spectral image taken by a Philips vesta webcam. Image Credit: lightfrominfinity.org
So the discovery of such signature evidence through spectrography with instruments on platforms like the Hubble Telescope, on spheres that exist in other solar systems, makes for a better understanding and pushes the envelop of current scientific techniques.
This excerpted from WIRED -
Molecular Basis of Life Discovered on Extrasolar Planet
By Alexis Madrigal, Wired - 03.19.08 6:15 PM
Scientists using the Hubble Space Telescope have for the first time found the telltale signature of methane, an organic molecule, in the atmosphere of a planet outside our solar system.
Methane is one of the chemicals of life, an organic compound in the class of molecules containing carbon. However, no life is likely to exist on the large, gaseous planet known as HD 189733b. Its daily temperatures can reach 1,340 degrees Fahrenheit.
"These measurements are a dress rehearsal for future searches for life," said Mark Swain, a scientist at NASA's Jet Propulsion Laboratory and the lead author of a new study that appears in Nature tomorrow. "If we were able to detect [methane] on a more hospitable planet in the future, it would really be something exciting."
Since the discovery of the first so-called exoplanet 13 years ago, scientists have been able to glean little about the 270-plus known extrasolar planets. Even rough sizes and masses have been calculated for a mere 30 of those planets. It is only in the last year that scientists have begun to characterize the conditions on these planets, like their surface temperatures, and as in this case, the chemical composition of their atmosphere. Such findings not only shed light on other solar systems, but also on our own.
HD 189733b, a so-called "hot Jupiter," located 63 light years away, has proven a boon for scientists studying exoplanets. Its large size and proximity to its star mean that it dims the star's light more than any other known exoplanet. Combine that with its home star's high brightness, and scientists find that the system creates the best viewing conditions of any known extrasolar system.
At different wavelengths, every atom and molecule has its own telltale footprint, so scientists can convert what are known as absorption spectra into the chemical composition of the object they're looking at.
The technique, known as spectrography, will remain the main scientific technique for learning about exoplanets into the future with planets that could support life.
"Twenty years from now, we'll be able to do this for superearths," said Jonathan Fortney, an astronomy professor at the University of California, Santa Cruz. "We'll be able to see methane in the atmosphere of an Earth-like planet."
To do so, however, astronomers will need new tools. Swain's team used Hubble's Near Infrared Camera and Multi-Object Spectrometer to capture rough spectrographic data. They were forced to use the low-resolution tool because the dedicated instrument for spectrography -- the Space Telescope Imaging Spectrograph -- broke in 2003, Redfield said.
"The STIS spectrograph would get resolutions several orders of magnitude higher than the tool they used," said Seth Redfield, a Hubble postdoctoral fellow at the University of Texas at Austin, who previously identified sodium in HD 189733b's atmosphere.
He said NASA was planning to try to fix the tool in late summer of this year, and that access to the tool could lead to new discoveries. In the meantime, scientists will keep plugging away, revealing the properties of planets dozens of light years away, molecule by molecule.
"We know so little observationally about these planetary atmospheres that any sort of measurement is tremendously exciting," Redfield said.