Tuesday, February 4, 2014

Will Astronomers Ever Find Another Earth?

By Phil Plait

One of the biggest questions in astronomical research right now is quite simple to ask but extremely difficult to answer: In the depths of space, is there an Earth-like planet somewhere orbiting a Sun-like star?

The answer is rather surprising: almost certainly yes. We haven’t found a precise twin of Earth yet, but we’ve come mighty close. In fact, it’s likely that there are millions, perhaps billions, of planets like ours in the Milky Way alone. But right now, at this moment, we only know of one for sure: ours.

So when will we actually see that blue-green dot in our telescopes?

The search for alien worlds orbiting other stars—exoplanets—has gone on a long time. Quite a few were thought to have been seen, but they were on the thin, hairy edge of what the technology could do and were later shown to be false positives.

Things changed in 1992. Using sophisticated timing techniques, scientists found the very first confirmed planets, which were orbiting a pulsar, the ultradense core of an exploded supernova. That turns out not to be the most hospitable place in the Universe, what with the pulsar spewing out enough X-rays to thoroughly fry surrounding space. Planets they are, Earth-like they are not.

But then in 1995 came the big announcement: A planet had been found orbiting the star 51 Pegasi. The star is similar to the Sun, but the planet was a shock: It had 0.4 times the mass of Jupiter (150 times the Earth’s mass), but it orbited the star a mere 8 million kilometers (5 million miles) from the star! It screamed around the star in just 4.2 days, a far smaller and shorter orbit than had been thought possible.

The method used to find this planet is called the Doppler technique. When a planet orbits a star, its gravity tugs on the star. The planet makes a big circle while the star makes a smaller one. As the star approaches us in that cycle, its light gets compressed a bit, shifting it to shorter wavelengths. When it recedes from us, the opposite happens. This is essentially the same physics that makes a motorcycle make that “EEEEeeeeeeooooooooowwwwwww” sound as it passes you, what scientists call the Doppler effect.

Read the rest here.


  1. Most astronomy, relativistic physics, and practically all astrophysics, is utter garbage.

    See www.thunderbolts.info for how things more likely work.

    1. "Most", except for the parts that have been cherrypicked for use in "the Electric Universe paradigm".

      Now, who was Georg Friedrich Bernhard Riemann? Why should we care about his work? And what might the work of James Clerk Maxwell have to do with the interesting hypothesis that "a web of electrical circuitry connects and unifies all of nature"?

  2. I like a lot of Phil Plait's writing and mostly enjoyed his "Death from the Skies!" book, but he dropped all pretense of science and shilled for "global warming" in the last couple chapters. The abrupt change in tone from measured statements about asteroids, gamma ray bursts, black holes, etc. to unsubstantiated foot-stomping over the discredited anthropogenic global warming hypothesis made me question his sanity.

    Likewise, the search for "another earth" strikes me as a lot of rubbish. Even if astronomers could observe other planets so many light years away and even if they saw and identified water, there's that little matter of HAVING NO EFFING CLUE WHERE LIFE CAME FROM IN THE FIRST PLACE. As for colonizing a lifeless world that has water, how does anyone imagine humans could conceivably travel to such a place?

    It's nice to dream, but come on.

    Also, the answer to the

    1. Plait is a talented practitioner and teacher of astronomy. Too bad about his constant ultracrepidarian pronouncements on climatology, epidemiology, and public policy. He's at his best when he sticks to his "holy gee wow the cosmos is blowing my mind" schtick.

    2. Ohhhh, I can't wait to look up ULTRACREPIDARIAN

      Sounds like an awesome word!

      (No snark-- I'm dead serious...unless you just made it up and I will hunt you down and CUT you!)

  3. The cynic in me says there isn't another Earth. This is it folks. Is this wrong? Prove it.

    Besides, even if there is it's probably hundreds of thousands or millions of light years away. How are we supposed to get there?

    1. Details about the distance won't matter. If another Earth-like planet is found, Paul Krugman will have an excuse for whipping up worldwide paranoia about an invasion by aliens, nearly all of them imaginary. But at least our economic troubles will be solved in about 18 months, or so he claims.

  4. More importantly, if they do, will they give a shit...

  5. Folks could also are high school Astronomer Jobs Zjob4u accountable for training college students, arranging instructional strategies, and also entail independently throughout instructional meetings.