A group of scientists announced at NASA headquarters Aug. 31 that they found two new planets outside of the solar system, a discovery that one AU professor said is not very surprising, considering the astronomically high number of expected planets in the universe.
"The scientific community expected [the planets]," AU physics professor and former university president Richard Berendzen said. "The problem was, we didn't have the technology to find them until now."
Both of the planets are within 51 light-years of Earth, according to NASA Planet Quest.
One of the planets circles the dwarf star Gilese 436, which is located in the Leo constellation, according to NASA. The planet flies about 2.6 million miles around the star every 2.6 days.
Though the planet is much closer to its star than Earth is to the sun, Barbara McArthur, a scientist at the University of Texas-Austin who helped find the planets, said that Gilese 436 is also much smaller than the sun.
The temperature of the planet that circles it is estimated at 698 degrees Fahrenheit - a cool temperature given the planet's closeness to the star. Temperatures there could dip down to 392 degrees or colder.
What was surprising about the newly discovered planets were their size and makeup.
The 135 planets previously discovered outside of the solar system have been large and gaseous, much like the planet Jupiter, said Geoffrey Marcy, an astronomer at the University of California-Berkeley who helped find the new discoveries.
"The new planets are between 15 and 21 Earth masses and are probably rock and ice, with some gas as an atmosphere," Marcy said.
However, life might be possible on these planets.
"[The team of astronomers] that discovered this planet suggested that it could have a habitable ring where life could be possible," McArthur said.
The other planet was discovered circling the star 55 Cancri in the constellation Cancer, 41 million light-years away from Earth. A light-year is the distance light travels in a vacuum in one year, which is about 5.88 trillion miles. The planet has an orbit of 2.8 days and moves 3.6 million miles around its star. This is 4 percent of the distance between the Earth and the sun.
Unlike Gilese 436, 55 Cancri is about the same size as the sun. The expected temperature on the planet that circles it can rise to 2,700 degrees Fahrenheit because it is so close to the star.
This planet is the latest discovery in a system of three other planets circling 55 Cancri, McArthur said. This makes it the first "extrasolar quadruple system," she said.
The fact that the planets are small and may be rocky makes them similar to Earth, and thus more able to sustain life as we know it than a Jupiter-like planet.
"If the planet is rocky, then all the chemicals that can support life can be together on a 'surface,' rather than floating in an atmosphere of gas," McArthur said.
A team of European scientists discovered another planet slightly smaller than those discovered by the Americans, but they did so after American scientists reported their findings. The International Astronomical Union determines date of discovery by the date that researchers submit their papers for publication.
The group that includes Marcy submitted its paper to The Astrophysical Journal July 14, and McArthur's group followed Aug. 2. The Europeans did not report their findings until Aug. 25.
Berendzen said he isn't impressed with those who attack the space program, by claiming it takes too much money and isn't worth the results.
"It means that the universe is a whole lot bigger than just looking around you," Berendzen said. "There are overarching things which are out there." He added that astronomy is important to AU students. "There are implications for biology, chemistry, astronomy, for that matter, even theology. We're talking about the origin of life, are we alone, how did the universe begin? These are profound issues. It's really your world"
