Astronomers at the University of Washington have developed a new method of gauging the atmospheric pressure of exoplanets, or worlds beyond the solar system, by looking for a certain type of molecule.
And if there is life out in space, scientists may one day use this same technique to detect its biosignature — the telltale chemical signs of its presence — in the atmosphere of an alien world.
Understanding atmospheric pressure is key to knowing if conditions at the surface of a terrestrial, or rocky, exoplanet might allow liquid water, thus giving life a chance.
The method, devised by Amit Misra, a UW astronomy doctoral student, and co-authors, involves computer simulations of the chemistry of Earth’s own atmosphere that isolate what are called “dimer molecules” — pairs of molecules that tend to form at high pressures and densities in a planet’s atmosphere. There are many types of dimer molecules but this research focused only on those of oxygen. Misra is first author of the paper was published in the February issue of the journal Astrobiology.
The researchers ran simulations testing the spectrum of light in various wavelengths. Dimer molecules absorb light in a distinctive pattern, and the rate at which they form is sensitive to the pressure, or density, in the planet’s atmosphere.
“So the idea is that if we were able to do this for another planet, we could look for this characteristic pattern of absorption from dimer molecules to identify them,” Misra said. The presence of such molecules, he said, likely means the planet has at least one-quarter to one-third the pressure of Earth’s atmosphere.
Powerful telescopes soon to come online, such as the James Webb Space Telescope, scheduled for launch in 2018, may enable astronomers to use this method on distant exoplanets. With such enhanced tools, Misra said, astronomers might detect dimer molecules in actual exoplanet atmospheres, leading to a clear understanding of the planet’s atmosphere.
This research may also play a part in the greatest astronomical quest of all — the ongoing search for life in the cosmos.
That’s because the team realized along the way that oxygen dimer molecules are often more detectable in an atmosphere than other markers of oxygen. That’s important from a biological standpoint, Misra said.
“It’s tied to photosynthesis, and we have pretty good evidence that it’s hard to get a lot of oxygen in an atmosphere unless you have algae or plants that are producing it at a regular rate.
“So if we find a good target planet, and you could detect these dimer molecules — which might be possible within the next 10 to 15 years — that would not only tell you something about pressure, but actually tell you that there’s life on that planet.”
Misra’s UW co-author is Victoria Meadows, professor of astronomy; other co-authors are Mark Claire of Scotland’s University of St. Andrews and Dave Crisp of NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
The research was performed through the UW-based Virtual Planetary Laboratory and funded by NASA (Grant NNH05ZDA001C), as well as a grant from Advancing Science in America, Seattle chapter.
For more information, contact Misra at 440-554-6514 or firstname.lastname@example.org
Peter Kelley | EurekAlert!
Telescopes team up to find distant Uranus-sized planet through microlensing
31.07.2015 | NASA/Goddard Space Flight Center
California 'rain debt' equal to average full year of precipitation
31.07.2015 | NASA/Goddard Space Flight Center
Using ultracold atoms trapped in light crystals, scientists from the MPQ, LMU, and the Weizmann Institute observe a novel state of matter that never thermalizes.
What happens if one mixes cold and hot water? After some initial dynamics, one is left with lukewarm water—the system has thermalized to a new thermal...
Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.
The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and...
Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.
Joint BioEnergy Institute study identifies bacterial protein that is key to protecting rice against bacterial blight
A bacterial signal that when recognized by rice plants enables the plants to resist a devastating blight disease has been identified by a multi-national team...
Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.
By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for...
23.07.2015 | Event News
10.07.2015 | Event News
25.06.2015 | Event News
31.07.2015 | Trade Fair News
31.07.2015 | Transportation and Logistics
31.07.2015 | Physics and Astronomy