Posted on 09/15/2004 10:18:07 AM PDT by balrog666
Recent discoveries spark space race between Europeans and Americans to find another Earth
The announcement by American astronomers last week that they had discovered the two smallest planets yet orbiting nearby stars, trumped a small planet discovery by European scientists five days earlier and capped the latest round in a frenzied hunt for other worlds like Earth.
All three of these smaller planets belong to a new class of ''exoplanets'' - those that orbit stars other than our sun, the scientists said in a briefing last Tuesday. They define this new class by the planets' smaller mass - roughly 14 to 18 times the size of Earth and equivalent to Neptune in our solar system.
The two planets announced last Tuesday were spotted by two separate teams of U.S. researchers using telescopes in Hawaii and Texas. Scientists not involved in the projects lauded both, saying their planets should be recognized as the first discoveries of planets in this class - rather than the discovery of the Europeans, announced two weeks ago.
The dueling announcements reflect the intensity of the race to discover exoplanets. The big prize, of course, would be to find an Earth-sized planet capable of supporting life, but today's instruments cannot detect bodies that small.
''We can't quite see the Earthlike planets yet, but we are seeing their big brothers,'' said planet hunter Geoffrey Marcy of the University of California at Berkeley, a leader of one of the teams.
Using an Olympics analogy, other scientists said the American groups have tied for first place in the planet hunt and should share a gold medal.
They noted the Americans' findings have been accepted for publication by international science journals, while the discovery led by a pair of prominent Swiss astronomers still is being reviewed for publication.
''These two were submitted July and August, while the Swiss discovery is still in consideration,'' said planetary theorist Alan Boss of the Carnegie Institution in Washington, D.C., who did not participate in any of the discoveries.
''On that basis,'' he said of the Europeans, ''I would award them the bronze'' medal.
Over the past decade, astronomers have found as many as 135 planets orbiting various stars, but all of them are giant gas planets similar to Jupiter and Saturn.
Researchers don't know the composition of these new, smaller planets or what they actually look like.
In our solar system, Neptune and Uranus are of similar size and they are composed of an icy, rocky core enveloped in a thick atmosphere of hydrogen and helium. But they sit in the farthest reaches of our solar system.
By contrast, both of the new planets are very close to their stars, making them difficult to spot.
One of them orbits very close to the star named 55 Cancri, which is about the same size as our sun and located 41 light-years away in the constellation Cancer. The new planet was located by University of Texas-Austin astronomers using the Hobby-Eberly telescope in the Davis Mountains southeast of El Paso.
The star already had three known gas giant planets looping it in orbits that take anywhere from 14 to 4,520 days. The new planet is the innermost of the quartet, zooming around the star in 2.8 days from a distance of about 3 million miles.
Researchers acknowledged there probably are several different types of solar systems orbiting distant stars. But for now, the 55 Cancri system bears the closest resemblance to ours.
''This star is the premier lab for study of the formation and evolution of planetary systems,'' said astronomer Barbara McArthur, who led the Texas team.
The other new planet discovered by American scientists orbits a star called Gliese 436, that lies about 33 light-years from Earth in the direction of the constellation of Leo.
It was discovered by a team led by Marcy and Paul Butler of the Carnegie Institution using one of the twin telescopes atop Mauna Kea in Hawaii.
''Our ability to find planets in the Neptune-mass range tips the scales for finding other Earths sooner rather than later,'' Butler said.
Together, Marcy and Butler have spotted about half of the known exoplanets. They studied Gliese 436 for four years beginning in 2000.
Besides the exoplanet's size, what makes the discovery remarkable is that Gliese 436 is a red dwarf star that produces only 2 or 3 percent as much light as the Sun. Stars in this category account for 70 percent of the stars in the Milky Way galaxy, but until now, astronomers had not believed that such faint stars would yield new planets.
Now they are ''revamping'' their detection strategy to look at more dwarf stars. ''We estimate there is something like 20 billion planetary systems existing in our Milky Way galaxy alone,'' Butler said.
Meanwhile, the European team on Aug. 25 described its new object as a ''super-Earth.''
The planet was spotted in June orbiting a southern hemisphere star called mu Arae 50 light-years away in the constellation Alter. It orbits mu Arae every 9.5 days and has a temperature of more than 1,160 degrees.
Planetary Ping!
Thanks for the ping!
If true, that would mean many trillions of planetary systems throughout of the universe.
And some say no other life exists outside of earth. I'd say that would be stranger than there actually being life elsewhere.
Induction might say so, but there is no evidence so far. It might be more reasonable to say that it is highly possible there is life elsewhere. We just don't know at this time.
I can't imagine 200 trillion planetary systems, without even so much as a micorbe.
I would expect to find life on every ball of rock, and this is just extrapolating from the fact that there are microbes inside rocks and every other place we look on earth. I might be surprised if we fail to find life out there, even on the airless, waterless moon. Another planet with an animal/plant kingdom? That would be a surprise.
If the people of earth don't kill each other off, one way or another in the next 10,000 years, I wouldn't be surprised at all that discoveries would find planets teaming with life, both plant and animal type, and types we have yet to even imagine. Wouldn't that be cool?
It would be cool. I don't think we will be moving to planets as we move into space. I think we are going high tech with manufactured homes. Winnebago style. Some may settle planets, but most will be travelling most of the time. That means earth is our first and will be essentially our last planet even if we populate the entire galaxy. We will be moving into solar systems, but only to reprovision.
We have enough technology now if we wish to leave the solar system. What we don't have is a good enough reason to do so. It won't be cheap, though, even if we build our starships out of asteroid material and launch essentially nothing from the surface of earth.
It's not important how long it takes.
I'm pretty sure that today's rockets travel at no more than one percent of one percent of lightspeed, which is .0001c. At lightspeed, the trip would take 4 years. With our rockets, that's about 40,000 years.
Thanks for the ping. :-)
I was hoping you'd correct any error I made in post 15. I'm pretty sure I got it right, but I recognize when I'm likely to be over my head.
Sorry got in a hurry this morning. Will post on this tonight. :-)
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