Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

MIT, others ask 'What would E.T. see?'

21.12.2007
Team analyzes how alien astronomers would study Earth

As astronomers become more adept at searching for, and finding, planets orbiting other stars, it's natural to wonder if anybody is looking back. Now, a team of astronomers that includes a professor from MIT has figured out just what those alien eyes might see using technologies being developed by Earth's astronomers.

According to their analysis, among other things E.T. could probably tell that our planet's surface is divided between oceans and continents, and learn a little bit about the dynamics of our weather systems.

"Maybe somebody's looking at us right now, finding out what our rotation rate is - that is, the length of our day," says Sara Seager, associate professor of physics and the Ellen Swallow Richards Associate Professor of Planetary Sciences at MIT.

Seager, along with Enric Palle and colleagues at the Instituto Astrofisica del Canarias, in Spain, and Eric Ford (MIT class of 1999) of the University of Florida, have done a detailed analysis of what astronomers here and on other worlds could learn about a planet from very distant observations, using telescopes much more powerful than those currently available to Earth's astronomers. Their study, which has just been published online in the Astrophysical Journal, will appear in the journal's print edition in April.

Most of the planets astronomers have discovered beyond the Solar System have not actually been seen; rather, they have been indirectly observed by looking at the influence they exert on stars they orbit. But even with the most advanced telescopes planned by Earth's astronomers for use over the next several years, a planet orbiting another star would only appear as a single pixel-that is, a single point of light, with no detail except its brightness and color. By comparison, a simple cellphone camera typically takes pictures with about a million pixels, or one megapixel.

"The goal of [our] project was to see how much information you can extract" from very limited data, Seager says. The team's conclusion: a great deal of information about a planet can be gleaned from that single pixel and the way it changes over time.

The way of analyzing the data that Seager and her co-authors studied would work for any world that has continents and bodies of liquid on its surface plus clouds in its atmosphere, even if those were made of very different materials on an alien world. For example, icy worlds with seas of liquid methane, like Saturn's moon Titan, or very hot worlds with oceans of molten silicate (which is solid rock on Earth), would show up similarly across the vastness of space.

However, the method depends on clouds covering only part of a planet's surface, regardless of what each world is made of. So Titan, covered by perpetual global smog, would not give up the mysteries of its weather or rotation, nor would the hellishly hot Venus, with its complete shroud of clouds.

The key, the astronomers learned after sudying data from Earth's weather satellites, is that while clouds vary from day to day, there are overall patterns that stay relatively constant, associated with where arid or rainy landmasses are. Detecting those repeating patterns would allow distant astronomers to figure out the planet's rotation period because a brightening associated with clouds above a particular continent would show up regularly once each "day," whatever the length of that day might be. Once the day's length is determined, then any variations in that period would reveal the changing weather-that is, clouds in a different place than the average.

No telescope now in operation is capable of making the measurements that Seager and her team analyzed. But planned telescopes such as NASA's Kepler, set for launch in 2009, would be able to discover dozens or hundreds of Earth-like worlds. Then even more advanced space observatories being considered, such as NASA's Terrestrial Planet Finder, would allow the followup studies to learn about these planets' rotation and weather, and the composition of their atmospheres, Seager says.

The research was funded in part by a Ramon y Cajal fellowship for Palle, and a Hubble Fellowship grant for Ford and by NASA.

Patti Richards | MIT News Office
Further information:
http://web.mit.edu/newsoffice/www

More articles from Physics and Astronomy:

nachricht A better way to weigh millions of solitary stars
15.12.2017 | Vanderbilt University

nachricht A chip for environmental and health monitoring
15.12.2017 | Friedrich-Alexander-Universität Erlangen-Nürnberg

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>