Odds against Earth-like planets

http://news.bbc.co.uk/2/hi/science/nature/2701977.stm ^ | January 28, 2003 | Dr David Whitehouse

[conservativecorner]

In the beginning God created the heavens and the earth...Genesis 1

[Libertarianize the GOP]

http://www.freerepublic.com/perl/bump-list

[anobjectivist]

Hmm. The problem with any hypothesis about habitable planets is the technology we use to "discover" the existence of planets orbiting stars is based on the effects those planets have on their stars (wobbly stars, planet transits creating decrease in luminosity, doppler effect of orbiting star).

The methods we use to determine planets have a tendency only to report large (jupiter scale), close-orbiting planets. To my knowledge, even if we were able to go as far away from our own planet as we are from the stars being observed with jupiter like planets, and we looked back at our star, we would probably not detect any planet but jupiter/saturn if that. Our current technology makes it seem like we are alone in the universe but once we get an orbiting inteferometer working we'll be able to identify planets by more than just their effects on their host stars. (we could detect planets by infrared radiation, reflected light, etc., things that we cannot do realistically with 99.999999999999% of the stars out there with current technology) A whole new universe will be ours to see.

[Mr. K]

I think it is a miracle in itself that planets sustain (nearly) circular orbits- do you have any cluse how little it would take to knock them out of the precise balance of mass/speed that puts it into orbit? (circular OR otherwise)

[anobjectivist]

Additionally:

The fact that there are billions of stars in the universe and we have only detected around 100 of these stars with close, jupiter like planets suggests the opposite of what this article reports. In all likelyhood, the planets we are detecting are the rare ones (big enough to show up after observation with simple telescopes), the more common planets are too small or too far away from their host star to be observable by our current method. Thus, any real studies on the limited data that our technology affords at the moment should be taken as premature, incorrect guesses.

[Pres Raygun]

What the article doesn't state though is that planetary systems without Jupiter like outer planets cannot support advanced life either, because the large Jupiter like gas giants are required to keep catastrophic meteors from impacting any life bearing planets in the habital zone.

[Psycho_Bunny]

This article really reads like the work of someone desperate to make the news.

[Bloody Sam Roberts]

...and we looked back at our star, we would probably not detect any planet but jupiter/saturn if that.

I think the best analogy I've heard is that it is like trying to detect a speck of dust orbiting a 100 watt light buld from 100 meters away.

[anobjectivist]

To our limited knowledge of planetary formation, yes that would make sense, however life-bearing planets could have a possibility of surviving without jovian planets. The thing is they would have to age more (endure a longer period of bombardment) before life really takes off.

Also, I doubt that we can detect jovian planets at the same distance from our sun as jupiter except in the nearest stars.

[Dog Gone]

85 solar systems is not exactly a representative sampling of the galaxy, much less the entire universe.

If only 1 in 85 has an earthlike planet, how many would that make?

60 bazillion?

[Poohbah]

85 solar systems is not exactly a representative sampling of the galaxy, much less the entire universe.

If only 1 in 85 has an earthlike planet, how many would that make?

60 bazillion?

Give or take a kajillion :o)

[Burkeman1]

There are about 100 billion stars in the milky way alone. If only 0.01 percent had Earth like planets that still means ten million Earth like worlds just in our galaxy alone.

[MattinNJ]

bttt for later read.

[steve-b]

In general, other planetary systems fall into two types: those with Jupiter-like worlds circling close to their parent star, and those with more distant Jupiters in elliptical orbits.

These two cases (particularly the former) are considerably easier to detect than the case of a Jovian in a distant circular orbit. Thus, the available data shows a strong selection bias.

[anobjectivist]

Yup, and all we need is more sophisticated equipment orbiting somewhere (prefereably a lagrange point) with big enough detectors and an interferometer setup and we might be able to actually see a few blue pixels coming from an earth-like planet. And once we get the light from these planets, we could do a simple spectrum analysis and find out what we have.

[chilepepper]

I've heard this argument before and believe it is the exact inverse of playing the lottery: don't fight against billions and billions of stars

you cannot win such a bet. there is no doubt in my mind that there are MANY planets out there that will support life, and a fair sized subset of those will be very earthlike...

[Mr. K]

but getting them into an orbit - out of the infinite number of places they could go is astounding

[RightWhale]

This is the central hypothesis of the book "Rare Earth," copyright 2000, Peter D. Ward and Donald Brownlee. Since this contradicts Sagan's hypothesis, the idea was not popular at the time. However, it is gaining acceptance.