"We are looking for Earth-like planets in the habitable zone of their star, a band not too hot nor too cold for life to exist," says Darren M. Williams, associate professor of physics and astronomy, Penn State Erie, the Behrend College. "We also want to know if there is water on these planets."
For life to exist, planets must have habitable temperatures throughout a period long enough for life to evolve. For life as we know it, the planet must have a significant amount of water. Scientists already know how to determine the distance a planet orbits from its star, and analysis of light interacting with molecules in the atmosphere can indicate if water exists. However, Williams and Eric Gaidos, associate professor of geobiology, University of Hawaii, want to identify planets with water on their surfaces.
The researchers' method, reported in an upcoming issue of Icarus and currently available online, relies on the reflective properties of water.
"A planet like Venus, with a dense atmosphere, will scatter the sunlight in all directions," Williams says. "If you look at Venus in phases, when it is full, it is brightest and when it is crescent, it is faintest."
When a planet is full in respect to its sun with the whole disk illuminated, water would actually be darker than dirt. However, when a planet is in crescent, with the sun glancing off the watery surface, the reflection will be brightest.
The image of the Blue Marble, taken by Apollo 17 in December 1972, is striking because the Earth is 70 percent covered in water. The researchers believe that large enough amounts of water will provide a glint of light visible in the infrared and visible spectrum if they watch the planet for long enough.
"We are going to look at the planets for a long time," says Williams. "They reflect one billionth or one ten billionth of their sun. To gain enough light to see a dot requires observation over two weeks with the kinds of telescopes we are imagining. If we stare that long, unless the planet is rotating very slowly, different sides of the planet will come through our field of view. If the planet is a mix of water, we are going to see the mix travel around the planet."
The researchers want to monitor the light curve of a distant planet as the planet spins on its axis and moves around its star. By looking at the changes in brightness, correlated to the planet's phase, they should be able to tell if the planet has liquid oceans. If the temperatures are correct, the liquid is probably water.
While there are currently no telescopes capable of identifying watery planets, astronomers hope that a terrestrial planet finder telescope will orbit the earth in the next 10 to 20 years. In the meantime, the Penn State researcher has arranged for the current Mars Express and Venus Express missions of the European Space Agency, to look back at the Earth occasionally from a great distance and observe what our watery planet looks like in various phases.
"Any time that the Earth is in a crescent phase as viewed by a distant space vehicle, we should take advantage of the situation and look back at the Earth," says Williams.
A'ndrea Elyse Messer | EurekAlert!
Study offers new theoretical approach to describing non-equilibrium phase transitions
27.04.2017 | DOE/Argonne National Laboratory
SwRI-led team discovers lull in Mars' giant impact history
26.04.2017 | Southwest Research Institute
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
27.04.2017 | Life Sciences
27.04.2017 | Physics and Astronomy
27.04.2017 | Earth Sciences