Mapping Clouds on Exoplanet Kepler-7b

NASA's depiction of an exoplanet discovered last year. (Credit: NASA)

NASA’s depiction of an exoplanet discovered last year. (Credit: NASA)

An international team, with participation from the University of Bern, has produced the first map of clouds on an exoplanet using the Kepler Space Telescope. Studying the atmospheres of exoplanets is the path towards ultimately identifying life elsewhere in the Universe. Understanding the role of clouds in exoplanet atmospheres is a necessary ingredient in the cosmic hunt for life. Read More →

A Universe of New Worlds to Discover & Explore

Exoplanets

In 1992, scientists made one of the most significant discoveries in the history of astronomy; the first confirmed detection of an extrasolar planet. For many decades, it had been widely believed that planets existed around stars other than our own, but it was not until the discovery of two planets orbiting a distant star some 1000 light years away (1 light year = about 6 trillion miles) that their existence was proven beyond doubt. As detection methods advance, particularly thanks to the highly successful Kepler Space Telescope launched in 2009, new alien worlds are being discovered almost every week. Read More →

Future Mission to 51 Pegasi

Due to their proximity to Earth, many of the closest star systems have been extensively studied. When the mass media gets their hands on research, they go wild with it. This is a very human response. Naturally, many individuals want to find proof of extraterrestrial life. Other people want to find places where humanity can expand. Some people might simply have some sort of fantasy fulfilled by being an armchair astronaut.

In 1995 astronomers announced that they had discovered a planet, 51 Pegasi B, in orbit around its star, 51 Pegasi – the first exoplanet found orbiting a star similar to the Sun. If one were to travel 48 light-years from this world, they might happen upon a fifth-magnitude star with a mass that’s almost 47 percent higher than that of Jupiter. The planet in that system orbits extremely close to the stellar body. This might very well suggest that the world could never have supported life.

However, that means very little and long-range planning and missions to these systems should still be planned. Though faster than light travel is still out of reach, even conventional systems could theoretically take an artificial intelligence unit to another star system. While it might take decades to reach another world, the whole of humanity would be better for it – especially if life were discovered.

I’m all for going back to the moon (human exploration). It’s a feasible idea (given that we’ve done it before) and certainly a candidate for early space colonization. That being said, I think we should stop focusing on manned missions to Mars [PDF] for now, and focus instead on sending machines to conduct long-term planetary exploration and discovery missions. Ancestors of today’s scientists will surely reap the benefits of such journeys in the far future as a result of our efforts right now.

Image Credit: BBC

Transit Photometry for Planetary Discovery

Credit: ESA/University of Florida

Transit photometry is a technique astronomers use to detect extrasolar planets. Planetary orbits often force extrasolar bodies to pass between their suns and telescopes on Earth. This causes a drop in the amount of starlight detected by local astronomers. By measuring this drop in light, the relative location of planets can be charted.

Observing the transit pathways that extrasolar bodies take reveals several important pieces of information about them. Size is usually easy to determine from these sorts of studies. Considering that observations can’t be made in person, this might very well be the best way to discover their size.

Studies that take a look at transit photometry data are generally able to calculate the orbital periods of various extrasolar planets. Individuals with an interest in the search for intelligent life might also want to consider what size and orbital have to say about the theoretical habitable zone of another world. Life forms that resemble those found on Earth would most likely be found on planets with similar habitable areas.

Futuristic explorers will quite possibly use the information collected today when trying to select planets for terraforming. Since generational ship missions will need to be carefully planned, collecting accurate data today might save lives tomorrow.

Introduction to the La Silla Observatory

Astronomers have long been excited about astronomy discoveries from the La Silla Observatory in Chile. The observatory contains the High Accuracy Radial Velocity Planet Searcher. This is one of the most accurate spectrometers in the world. The High Accuracy Radial Velocity Planet Searcher works by watching the wavelengths of stars as they approach the Earth and move away from our planet. The High Accuracy Radial Velocity Planet Searcher has been used to study stars and planets since 2003. Read More →

Keck Interferometer Winding Down

The Keck Interferometer, linking twin telescopes located atop Mauna Kea in Hawaii and part of NASA’s search for extrasolar planets, now faces its final months of operation due to NASA budget cuts. It is scheduled to shut down in July, though the two telescopes it linked will continue to observe independently of one another. While the Keck telescopes are among the largest in the world for infrared and near-optical observation, financial and political obstacles prevented them from ever reaching their full potential.

Built in the 1990s, the Keck’s twin telescopes were to have been joined by four smaller “outrigger” telescopes that would have dramatically increased the Interferometer’s ability to observe small areas of sky. The telescopes’ combined power would have made visible planets the size of Uranus orbiting nearby stars.

NASA actually built the outriggers several years ago, but they never reached Mauna Kea. NASA withdrew their funding after setbacks in other programs meant to search for exoplanets. This, added to objections from native Hawaiians who have long opposed the presence of an observatory atop what they consider a sacred mountain, along with a court-ordered halt to expansion of the observatory to assess its environmental impact, sounded the death knell for the project. Last year, NASA ultimately withdrew funding for the Interferometer itself.

Keck in Motion from Andrew Cooper on Vimeo.

Image: The Keck Interferometer, with the telescopes’ doors open to equalize temperature inside and outside of the domes. Credit: NASA/JPL

Let’s Explore Photosynthesis on Exoplanets

Imagine an astronaut stepping out of a spacecraft onto the surface of an extrasolar planet that is capable of sustaining life. Now imagine the astronaut is greeted by the sight of red colored trees and grass. Such a scenario could be more reality than science fiction because of the variances in photosynthesis theorized to exist in other parts of the Milky Way Galaxy.

Photosynthesis occurs in plants when they use sunlight to create foods from carbon dioxide and water. This process of converting energy from sunlight into chemical energy produces oxygen and causes chlorophyll to form. It is chlorophyll that is responsible for imbuing plants with a healthy green color. The reason this happens is because chlorophyll absorbs more blue and red light waves and fewer green light waves from sunlight. Reflecting the green light waves is what causes the plants to appear green to the human eye.

When the Sun in our solar system radiates light, it reaches the Earth in a particular distribution of colors. As this sunlight passes through the Earth’s atmosphere, the various gases that comprise the atmosphere filter out certain colors before they strike the surface of the Earth. Much of the color that is not absorbed in the atmosphere is red, blue or green. Plants tend to absorb a greater amount of red and blue rays and reflect back green.

Some scientists think that plant life growing under the rays of an extraterrestrial sun could reflect colors other than green after the photosynthesis process is completed. The color that is most commonly visible on alien plants correlates with how colors are distributed in the light radiated by the parent star that strikes the surface of the extraterrestrial world.

The spectral type of a main sequence star can have a direct impact on the coloring of plants. For that reason, coloring can vary from star to star if the spectral type for each star also shows some variance. In a scientific paper published in the March, 2007 issue of Astrobiology magazine, a team of scientists examined how light emitted by another sun would appear from the vantage point of a planet orbiting that host star. Nancy Kiang, author of the paper, said the scientific team determined that the atmosphere of any extrasolar Earth-like planet would feature a chemical composition that is compatible with the chemical composition of its host star. How light from that star is seen on the planet’s surface would be affected by how it is filtered through the atmosphere as it reaches the surface.

Kiang, who works with the Goddard Institute for Space Sciences at NASA, and her team conducted an extensive study where they modeled how sunlight would reach the surface of Earth-sized planets that are hospitable to life from stars of varying spectral types. Kiang’s team speculated that each planet could experience different dominant colors that emerge in plants through photosynthesis based on how hot or cool the sun is that is anchoring that solar system.

Plant life existing on other worlds is not guaranteed to mimic the appearance of plants we are accustomed to seeing on Earth. Planets revolving around a blue star could feature plant life that has a dominant color of yellow or orange and this could lend to forests that boast autumn type colors throughout the growing season on those planets. If a habitable world is located in a binary star system or multi-star system, it could cause some exotic variations in how the plant life grows and appears to the human eye after going through photosynthesis. These planets could have plants that are almost black in color.

In the case of habitable planets around red dwarf stars, all plant life would likely exist underwater. The proximity of the habitable zone around the star would make it difficult for plants to fend off ultraviolet radiation because they could not generate enough energy from infrared light through photosynthesis to create sufficient oxygen to block ultraviolet radiation penetrating the atmosphere.

The idea that differences exist in the photosynthesis process from one planet to the next changes how astrobiologists search for evidence of life on other worlds outside our own solar system. It reinforces the idea that plant and animal life alike have evolved and adapted to fit the unique conditions of this Earth as well as reinforcing the notion that life on other habitable planets would evolve to survive and thrive in a similar manner on other planets. What do you think? Is photosynthesis the same on all planets or do you think it will be vastly different?

References: 
Kiang, N., Siefert, J., Govindjee, ., & Blankenship, R. (2007). Spectral Signatures of Photosynthesis. I. Review of Earth Organisms Astrobiology, 7 (1), 222-251 DOI: 10.1089/ast.2006.0105

Kiang, N., Segura, A., Tinetti, G., Govindjee, ., Blankenship, R., Cohen, M., Siefert, J., Crisp, D., & Meadows, V. (2007). Spectral Signatures of Photosynthesis. II. Coevolution with Other Stars And The Atmosphere on Extrasolar Worlds Astrobiology, 7 (1), 252-274 DOI: 10.1089/ast.2006.0108

Artist’s Impression of an Exoplanet with Moons, Orbiting the Star HD70642 (Photo Credit: David A. Hardy, Astroart.org © PPARC)

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