"We can watch for years and see almost nothing happen. This is bad news for people trying to understand Titan's meteorological cycle, as not only do things happen infrequently, but we tend to miss them when they DO happen, because nobody wants to waste time on big telescopes—which you need to study where the clouds are and what is happening to them—looking at things that don't happen," explains Brown, the Richard and Barbara Rosenberg Professor of Planetary Astronomy.
Schaller, now a Hubble Postdoctoral Fellow at the University of Arizona, Brown, and their colleages; Henry Roe, a former Caltech postdoctoral scholar in Brown's group, now at the Lowell Observatory in Flagstaff; and Tapio Schneider, a professor of environmental science and engineering at Caltech, describe their work, and its implications for climate on Titan, in the August 13 issue of Nature.
"A couple of years ago, we set up a highly efficient system on a smaller telescope to figure out when to use the biggest telescopes," Brown says. The first telescope, NASA's Infrared Telescope Facility, on Mauna Kea, takes a spectrum of Titan almost every single night. "From that we can't tell much, but we can say 'no clouds,' 'a few clouds,' or, if we get lucky 'monster clouds,'" he explains.
Schaller explains, "The period during which I was collecting data for my thesis, sadly, corresponded entirely to an extended period of essentially no clouds, so we never really got to show the full power of the combined telescopes. But then, after finishing and turning in my thesis, I walked back across campus to my office to look at the data from the previous night to find that Titan suddenly had the biggest clouds ever. I like to think it was Titan's graduation gift to me. Or perhaps a bad joke."
The day after the telescope's big find (and Schaller's thesis submission), Schaller, Brown, and Roe began tracking the clouds with the large Gemini telescope on Mauna Kea and watched this system evolve for a month. "And what a cool show it was," Brown says.
"The first cloud was seen near the tropics and was caused by a still-mysterious process, but it behaved almost like an explosion in the atmosphere, setting off waves that traveled around the planet, triggering their own clouds. Within days a huge cloud system had covered the south pole, and sporadic clouds were seen all the way up to the equator."
Schneider, an expert on atmospheric circulations, was instrumental in helping to sort out the complicated chain of events that followed the initial outburst of cloud activity.
"The monthlong event has many important implications for understanding the hydrological cycle on Titan," says Brown, "but one of the reasons I am most excited about it is that it shows clouds near the equator—where the [European Space Agency's] Huygens probe landed—for the first time. For a while now, people have speculated that the equatorial regions are simply too dry to ever have significant clouds."
And yet, the images snapped by the Huygens probe in January 2005, as it descended through Titan's soupy atmosphere and toward the surface, revealed small-scale channels and streams, which looked just like features created by fluids—by water, here on Earth, and on Titan, probably by liquid methane.
Experts had speculated for years on how there could be streams and channels in a region with no rain. The new results suggest those speculations may prove unneccessary. "No one considered how storms in one location can trigger them in many other locations," says Brown.
The paper, "Storms in the tropics of Titan," appears in the August 13 issue of Nature. The research was supported by a Hubble Postdoctoral Fellowship (to Schaller), the NASA Planetary Astronomy Program, and a Planetary Astronomy Grant from the National Science Foundation.
Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst
Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
27.03.2017 | Health and Medicine
27.03.2017 | Life Sciences
27.03.2017 | Earth Sciences