Planetary System Similar to Sol 379
sgtwilko writes "The BBC News site has an article about how astronomers have found several new planets including some that have a similar distribution to our own Solar System. They are finding planetary systems that are more and more like the one in which the Earth resides. It's only a matter of time until the Terrestrial Planet Finder program gets going and finds another Earth." There's another story on space.com. Update: 06/13 21:51 GMT by M : Space News and Wired have stories as well, with spiffy graphics and artists' renderings and so on.
Reason we can't detect planets the size of earth. (Score:5, Informative)
Currently, they have 2 ways (that I'm familiar with) to find an extra-solar planet. First, they can look for a "wobble" in the path the star takes. This wobble is caused by the gravitational pull of a large planet orbiting the star. Earth is so small that the tiny wobble caused by a planet similar in size would be impossible to view; or at least it would disappear with the systematical error.
The other way I've heard of to find extra-solar planets is similar to an eclipse. When the planet comes between the star and Earth, we can measure the changes in luminosity of the star. Obviously, with planets with small orbits, we can determine how quickly the planet orbits the star because of the pattern in the luminosity. Again, we can't detect earth size planets since earth is just too small.
Didn't you read the article (Score:5, Informative)
The astronomers said that an Earthlike planet _could_ survive in an orbit between the two large ones. Given a choice between your guess that it would get ripped to shreds, and the opinions of professional astronomers who've studied this specific solar system, and concluded that an Earthlike planet could be there, I'm going to side with the astronomers.
Re:What do Christians think about this? (Score:3, Informative)
What does the Bible say about intelligent life on other planets? [christiananswers.net]
Re:Progress? (Score:2, Informative)
To use your fish analogy, we're using wimpy hooks and catching small fry. As we get bigger and stronger hooks we keep pulling bigger fish. It's therefore reasonable to proceed with buying even bigger hooks, in the hopes that we haven't yet caught the biggest fish out there yet.
Re:What do Christians think about this? (Score:3, Informative)
Some Christians, however, do not understand this concept. This is the scariest glimpse into these peoples' minds I have from personal experience. When I was in the 9th grade, about 10 years ago, several of my friends at school and I were arguing about creation and evolution. One of the girls was a southern Baptist, and said her church was having a lecture on the topic for their youth group the next week. So the six or so of us decided to go. The guy leading the discussion was, of course, pro-creation, and that's fine...it's what I expected to find at a Baptist church event. Now, during the course of the lecture he asked the audience, "How old is the Earth?" One young adult raised his hand and responded "ten thousand years." Another said 6k. I raised my hand and said, "Four and a half billion years old."
They laughed at me. The entire audience turned around and laughed at me. I was speechless. I couldn't imagine that even being a topic of debate. The speaker went on to inform us that the Earth was, in fact, only six thousand years old, because the Old Testament listed the various ages of people who lived since Adam up until times of historical record, and with a little math... Draw your on conclusions, but that incident alone taught me I would have to approach my faith with a heavy dose of skepticism, so I wouldn't wind up spouting impossibilities simply because they're written in a book.
Re:why so keen on earth-sized? (Score:3, Informative)
As for smaller planets, you end up with situations like Mars. Mars has an atmosphere, although it has less than 1% of the air pressure that Earth has.
Venus has sufficient atmosphere, but its proximity to the sun, as well as the contents of its atmosphere, creates an environment that's too hot for "conventional" life to survive.
Of course, you also have the issue of habitable zones and their relation to the size of the sun. Consider our solar system as one that works. We're not too close, nor too far away from the sun, and the sun has 10 billion years of life (half of which it has expended already). Say we're looking at a larger star, like a blue giant. The planet could orbit further away and maintain the same temperate zone, but in 10 million years that sun is going to go supernova and any life will have not had enough time to evolve from inception. It took longer than that just for the Earth to cool down.
Large planets orbiting close to the sun present a problem. The primary concern is how they got there. Chances are good that they didn't form that close to the star, but formed further out then migrated inward to their present positions. If this is the case, its a darn good chance that any planets within the habitable zones will have either collided with the gas giant or been kicked out of the solar system.
The lack of any gas giants is also a problem. Jupiter does a nice job of attracting and "removing" potential threats to Earth, mostly the very large rocks. Without the gas giants out there to help us out, the Earth would get battered far more frequently than it does. Life can handle a huge hit once every 60 million years or so. Long term evolution would be severely hampered, however, if it happened more frequently.
A potential alternative to the current solar system is a gas giant located in the habitable zone with a earth sized moon. The moons of Juipter would have a significantly more viable climate if they were orbiting at 1 AU. However, this would present other dificulties, namely tidal lock. The moon would have to be sufficiently close to the planet so it didn't roast any one side for any significant length of time, however, the planet itself would block the light to the moon, so the moon would have one side that was perpetually frozen and the other side that had to endure long days and long nights. And any moon close enough to the planet to orbit quickly enough would have severe tidal problems... think IO.
So anyway, our best bet... is to find a solar system that resembles ours. At least until we find another model that works. Sorry about the extended rant.
-Restil
Not quite as far as quoted (Score:3, Informative)
55 Cancri is located 41 million light-years from the Earth, in the constellation of Cancer. The star, believed to be around five billion years old, is visible to the naked eye, astronomers said.
HA! I don't think so. That's about 20 times the distance to the Andromeda Galaxy. Nice how the people they have writing these things up have a good grasp on the fundamentals of the subject matter.