Scientists predict nongreen plants on other planets

April 11, 2007
Scientists predict nongreen plants on other planets

In the process of photosynthesis, plants convert energy from the sun into chemical energy in the form of glucose, or sugar. The chlorophyll in plants absorbs more blue and red light from sunlight, and less green light. Chlorophyll is green, because it reflects green light more than blue and red light. Credit: NASA Ames

NASA scientists believe they have found a way to predict the color of plants on planets in other solar systems.

Green, yellow or even red-dominant plants may live on extra-solar planets, according to scientists whose two scientific papers appear in the March issue of the journal, Astrobiology. The scientists studied light absorbed and reflected by organisms on Earth, and determined that if astronomers were to look at the light given off by planets circling distant stars, they might predict that some planets have mostly non-green plants.

"We can identify the strongest candidate wavelengths of light for the dominant color of photosynthesis on another planet," said Nancy Kiang, lead author of the study and a biometeorologist at NASA's Goddard Institute for Space Studies, New York. Kiang worked with a team of scientists from the Virtual Planetary Laboratory (VPL) at the California Institute of Technology, Pasadena, Calif. VPL was formed as part of the NASA Astrobiology Institute (NAI), based at the NASA Ames Research Center in California’s Silicon Valley.

"This work broadens our understanding of how life may be detected on Earth-like planets around other stars, while simultaneously improving our understanding of life on Earth," said Carl Pilcher, director of the NAI at NASA Ames. "This approach -- studying Earth life to guide our search for life on other worlds -- is the essence of astrobiology."

Kiang and her colleagues calculated what the stellar light would look like at the surface of Earth-like planets whose atmospheric chemistry is consistent with the different types of stars they orbit. By looking at the changes in that light through different atmospheres, researchers identified colors that would be most favorable for photosynthesis on other planets.

This new research narrows the range of colors that scientists would expect to see when photosynthesis is occurring on extrasolar planets. Each planet will have different dominant colors for photosynthesis, based on the planet’s atmosphere where the most light reaches the planet’s surface. The dominant photosynthesis might even be in the infrared.

"This work will help guide designs for future space telescopes that will study extrasolar planets, to see if they are habitable, and could have alien plants," said Victoria Meadows, an astronomer who heads the VPL. The VPL team is using a suite of computer models to simulate Earth-size planets and their light spectra as space telescopes would see them. The scientists' goal is to discover the likely range of habitable planets around other stars and to find out how these planets might appear to future planet-finding missions.

On Earth, Kiang and colleagues surveyed light absorbed and reflected by plants and some bacteria during photosynthesis, a process by which plants use energy from sunlight to produce sugar. Organisms that live in different light environments absorb the light colors that are most available. For example, there is a type of bacteria that inhabit murky waters where there is little visible light, and so they use infrared radiation during photosynthesis.

Scientists have long known that the chlorophyll in most plants on Earth absorbs blue and red light and less green light. Therefore, chlorophyll appears green. Although some green color is absorbed, it is less than the other colors. Previously, scientists thought plants are not efficient as they could be, because they do not use more green light.

According to scientists, the Sun has a specific distribution of colors of light, emitting more of some colors than others. Gases in Earth's air also filter sunlight, absorbing different colors. As a result, more red light particles reach Earth's surface than blue or green light particles, so plants use red light for photosynthesis. There is plenty of light for land plants, so they do not need to use extra green light. But not all stars have the same distribution of light colors as our Sun. Study scientists say they now realize that photosynthesis on extrasolar planets will not necessarily look the same as on Earth.

"It makes one appreciate how life on Earth is so intimately adapted to the special qualities of our home planet and Sun," said Kiang.

Source: Goddard Space Flight Center

4.2 /5 (25 votes)  

Rank 4.2 /5 (25 votes)
Tags

Related Stories
Relevant PhysicsForums posts
  • Scale of the Universe
    created6 hours ago
  • Titan's lack of impact craters
    createdFeb 09, 2012
  • Real pictures of black hole eating a star?
    createdFeb 08, 2012
  • Hypothetical way to travel faster than light, but not technically exceed lightspeed
    createdFeb 06, 2012
  • How do scientists monitor the Sun's activity?
    createdFeb 05, 2012
  • Search patterns in observational studies
    createdFeb 05, 2012
  • More from Physics Forums - General Astronomy

More news stories

Humans may have helped the decline of African rainforests 3000 years ago

(PhysOrg.com) -- Large areas of rainforests in Central Africa mysteriously disappeared over three thousand years ago, to be replaced by savannas. The prevailing theory has been that the cause was a change ...

Space & Earth / Environment

created 17 hours ago | popularity 4.2 / 5 (9) | comments 11 | with audio podcast report

Could Venus be shifting gear?

(PhysOrg.com) -- ESA’s Venus Express spacecraft has discovered that our cloud-covered neighbour spins a little slower than previously measured. Peering through the dense atmosphere in the infrared, the ...

Space & Earth / Space Exploration

created 13 hours ago | popularity 5 / 5 (7) | comments 7 | with audio podcast

NASA sees wide-eyed cyclone Jasmine

Cyclone Jasmine's eye has opened wider on NASA satellite imagery, as it moves through the Southern Pacific Ocean.

Space & Earth / Earth Sciences

created 5 hours ago | popularity 3.5 / 5 (2) | comments 1

NASA budget will axe Mars deal with Europe: scientists

US President Barack Obama's budget proposal to be submitted next week for 2013 will cut NASA's budget by 20 percent and eliminate a major partnership with Europe on Mars exploration, scientists said Thursday.

Space & Earth / Space Exploration

created 16 hours ago | popularity 5 / 5 (2) | comments 18

Mars Science Laboratory computer issue resolved

(PhysOrg.com) -- Engineers have found the root cause of a computer reset that occurred two months ago on NASA's Mars Science Laboratory and have determined how to correct it.

Space & Earth / Space Exploration

created 14 hours ago | popularity 4.7 / 5 (6) | comments 3 | with audio podcast


Google users warned of threat to smartphone wallets

Users of Google smartphone wallets were being warned on Friday that there is a way to crack pass codes intended to thwart thieves from going on illicit shopping sprees.

Anonymous knocks CIA website offline (Update)

The website of the Central Intelligence Agency was inaccessible on Friday after the hacker group Anonymous claimed to have knocked it offline.

Complex wiring of the nervous system may rely on a just a handful of genes and proteins

Researchers at the Salk Institute have discovered a startling feature of early brain development that helps to explain how complex neuron wiring patterns are programmed using just a handful of critical genes. ...

New error-correcting codes guarantee the fastest possible rate of data transmission

Error-correcting codes are one of the triumphs of the digital age. They’re a way of encoding information so that it can be transmitted across a communication channel — such as an optical fiber o ...

The power of estrogen -- male snakes attract other males

A new study has shown that boosting the estrogen levels of male garter snakes causes them to secrete the same pheromones that females use to attract suitors, and turned the males into just about the sexiest ...

New power source discovered

(PhysOrg.com) -- Researchers at the Massachusetts Institute of Technology (MIT) and RMIT University have made a breakthrough in energy storage and power generation.