White Dwarf Harbors Signs of Earth-Like Planets
Offline Original article can be found here.
updated 11:44 a.m. EDT, Fri August 17, 2007
White dwarf harbors signs of Earth-like planets
WASHINGTON (Reuters) -- Chemical elements observed around a burned-out star known as a white dwarf offer evidence Earth-like planets once orbited it, suggesting that worlds like our own may not be rare in the cosmos, scientists said Thursday.
Astronomers at the University of California, Los Angeles and University of Kiel in Germany studied a white dwarf called GD 362 located 150 light-years away in our Milky Way galaxy.
They figured out the chemical composition of a large asteroid that was ripped apart by gravitational forces as it approached GD 362, finding it was similar to the Earth's crust. It was rich in iron and calcium and low in carbon, much like a strong rock, they said.
The white dwarf is surrounded by dusty rings, probably made up of objects shredded as they ventured too close.
"It's probably quite similar to Saturn's rings," UCLA astronomer Michael Jura said in a telephone interview.
GD 362 once was a star similar to the sun. After billions of years, it ballooned into a "red giant" as part of its death process, expelling most of its outer material, then degenerated into a burnt-out remnant called a white dwarf.
The fact that the asteroid is so similar in make-up to the Earth, as well as the moon, indicates that rocky planets like our own may have orbited the star eons ago, Jura said.
And if such planets currently populate our solar system and existed in a planetary system around this white dwarf, they may well be fairly common in the universe, Jura added.
The research, based on observations made using the Keck I Telescope in Hawaii, will appear in the Astrophysical Journal.
It is the latest evidence found by astronomers indicating that planets like Earth are found outside our solar system.
European astronomers in April said they detected the most Earth-like planet yet outside the solar system orbiting a star 20.5 light-years from here, with temperatures that could harbor water and perhaps life.
A light year is about 6 trillion miles, the distance light travels in a year.
Jura said that his study's fresh evidence of Earth-like planets outside our solar system lends support to the possibility of extraterrestrial life.
"It's more than just daydreams," Jura said. "It's realistic to imagine that there are other places relatively similar to the Earth which would be a habitat. But, of course, we have no evidence whatsoever that they (alien life forms) do exist."
The rocky asteroid had a diameter of roughly 125 miles and may have been smashed by GD 362 between 100,000 and a million years ago, the astronomers said. While the white dwarf has a mass close to that of our sun, it has collapsed to such a point that its diameter is approximately that of the Earth.
GD 362 may offer a glimpse into our solar system's future. Astronomers believe the sun in perhaps 5 billion years will go through the same process, ending up as a white dwarf.
UCLA astronomer Benjamin Zuckerman said when our sun starts to expand in size and lose mass, the planets closest to the sun, Mercury and Venus, will get engulfed and destroyed. Other planets, probably including Earth, and the asteroid belt between Mars and Jupiter, will spiral out of their orbits, Zuckerman said.
Atheist Books, purchases on Amazon support the Rational Response Squad server.
- Login to post comments
I saw this article the other day.
They are finding more and more exoplantets at such an accelerated rate is it hard to keep up with all the new discoveries. I remember when the first couple of planets were discovered around other stars and the massive amount of media attention the dicovery recieved. Now, there are announcements on a seemingly daily basis regarding new planet discoveries that it seems the popular media is losing interest.
Sadly, you're correct. It's very much like our space program.
I'm old enough to remember how exciting it was when an astronaut orbited with earth. The whole thing was on television and we were all spellbound. We watched the preparations; we watched the blastoff; we watched live coverage from Houston.
When the first steps were taking on the moon, no one could move away from the television. Walter Cronkite was a permanent fixture in everyone's living room. We all watched as the spacecraft spashed into the ocean and the astronauts climbed aboard a ship.
Now the space program and the shuttles barely get mentioned as a top news story. It's still an amazing accomplishment, yet it's become "just another story" until there's a disaster like the Challenger.
Atheist Books, purchases on Amazon support the Rational Response Squad server.
Wow, just think. Perhaps this planet was very much like earth. Perhaps it had life or even intelligence on it, but now It's been burned out by its own little apocalypse.
It really makes you think how fleeting and fragile life is in the cosmos.
(donning wacko environmentalist cap)
I was thinking along the same lines a couple of days ago when one of my managers and I went to Target. He got a hot dog, and as he was opening his plastic mustard wrapper, I started wondering about the next species that will dominate earth. (I should mention that I firmly believe humans will cause the next great extinction, not an asteroid.)
Where we have fossils to tell us about the life forms that lived millions of years ago, the next species, should they gain enough intelligence to ask the questions, will have mustard wrappers.
I suppose an even more interesting question exists. If we can find out a few details about these earth like planets, are there beings who, millions of years from now, when the earth begins to be swallowed by our sun, will have the technology to deduce that we were here? Will we have impacted our planet enough that astronomers will be able to tell?
It's really an intriguing question! It prickles the hair on my arms to think that someone on a star not too far from us might have just discovered another planet like his own (if he happens to reproduce sexually and be male!) and is in the process of deducing that there is, in fact, a good possibility that there is life on it!
I wonder if they believe in a god?
Atheism isn't a lot like religion at all. Unless by "religion" you mean "not religion". --Ciarin
http://hambydammit.wordpress.com/
Books about atheism
Mustard wrappers, plastic milk jugs, all the non-degradable waste we put out every day and CDs with bad music.
Don't you wonder, too, that since social norms change*, if 1,000 years in the future - if the earth is still around - if archeologists will come across what we define as pornography and just think it's a bad documentary of some kind?
*I remember how outraged many people were when the words "son of a bitch" were uttered on the TV show Maude. Now swearing doesn't seem to be that big of a deal as long as the F-word isn't used. Does anyone remember the huge outcry against NYPD Blue before it ever hit the airwaves?
Atheist Books, purchases on Amazon support the Rational Response Squad server.