Earth seems to have its first fuzzy photos of alien planets outside our solar system.
The images show four likely planets that appear as specks of white that are nearly indecipherable except to the most eagle-eyed astronomers. But it is evidence of the existence of something far more cosmic than a blurry dot.
“It is a step on that road to understand if there are other planets like Earth and potentially life out there,” said astronomer Bruce Macintosh of the Lawrence Livermore National Lab, one of two teams of out-of-this-solar system photographers.
None of the four giant gaseous planets are remotely habitable or remotely like Earth. But they raise the possibility of others more hospitable, and Macintosh said it's only a matter of time before “we get a dot that's blue and Earthlike.”
The two groups of astronomers – one using the Hubble Space Telescope and the other using two ground telescopes – have captured images of the exoplanets, which are what scientists call planets that don't circle our sun. Both studies were being published in Thursday's online edition of the journal Science.
In the past 13 years, scientists have discovered more than 300 planets outside our solar system, but they have done so indirectly, by measuring changes in gravity, speed or light around stars.
NASA's space sciences chief Ed Weiler said the actual photos are important. He compared it to a hunt for elusive elephants: “For years we've been hearing the elephants, finding the tracks, seeing the trees knocked down by them, but we've never been able to snap a picture. Now we have a picture.”
There are disputes about whether these are the first exoplanet photos. Others have made earlier claims, but those pictures haven't been confirmed as planets or universally accepted yet. The photos released Thursday are being published in a scientifically prominent journal, but that still hasn't convinced all the experts. Alan Boss, an exoplanet expert at the Carnegie Institution of Washington, and Harvard exoplanet hunter Lisa Kaltenegger both said more study is needed to confirm these photos are proven planets and not just brown dwarf stars.
Nevertheless, the new photos provide the best evidence so far, according to NASA and others. The Hubble team this spring compared a 2006 photo to one of the same body taken by Hubble in 2004. The scientists used that to show that this was an object orbiting a star – making it less likely to be a dwarf star.
Macintosh's team used ground-based telescopes to spot three other planets orbiting a different star. That makes it less likely they are a pack of brown dwarf stars.
The planet discovered by Hubble is one of the smallest exoplanets found yet. It's somewhere between the size of Neptune and three times bigger than Jupiter. And it may have a Saturn-like ring.
It circles the star Fomalhaut, pronounced FUM-al-HUT, which is Arabic for “mouth of the fish.” It's in the constellation Piscis Austrinus and is relatively close by – a mere 148 trillion miles away, practically a next-door neighbor by galactic standards. The planet's temperature is around 260 degrees, but that's cool by comparison to other exoplanets.
The planet is only about 200 million years old, a baby compared to the more than 4 billion-year-old planets in our solar system. That's important to astronomers because they can study what Earth and planets in our solar system may have been like in their infancy, said Paul Kalas at the University of California, Berkeley. Kalas led the team using Hubble to discover Fomalhaut's planet.
One big reason the picture looks fuzzy is that the star Fomalhaut is 100 million times brighter than its planet.
The team led by Macintosh at Lawrence Livermore found its planets a little earlier, spotting the first one in 2007, but taking extra time to confirm the trio of planets circling a star in the Pegasus constellation. They are about 767 trillion miles away, but are actually visible with binoculars. The three planets are seven to 10 times larger than Jupiter, Macintosh said.