Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Can we please look for 'New Earth' at Alpha Centauri?

  1. Feb 26, 2005 #1
    Abdul Ahad wrote:

    "A Tiny Ray of Hope in the Eternal Darkness...

    Successfully locating an Earth-like planet in the habitable zone around one of the two principal 'suns' of the Alpha Centauri system will surely rank as one of the greatest discoveries in the entire history of science. Such a discovery would indeed be a 'revelation' and far outweigh all the extrasolar planets logged in all the world's scientific journals to date put together!

    A thousand Jupiters discovered circling in sub-Mercury orbits around red supergiants hundreds of light years away from Earth hardly stirs the imagination... Yet a single discovery of just *one* Earth-sized planet located within the habitable zones on the nearest cosmic shores beyond our solar system will revolutionise our science forever. "
    from the paper:
    http://www.astroscience.org/abdul-ahad/extrasolar-planets.htm [Broken]

    how much telescope time does one put on alpha centuri compared to all other stars, i wonder?
    Last edited by a moderator: May 1, 2017
  2. jcsd
  3. Feb 26, 2005 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Why would anyone want to look for an Earth-like planet around Alpha Centauri? It's a trinary system with two very close components. The likelihood of Earth-like planets here is, in fact, very small.

    Even if there were an Earth-like planet there, no existing telescope would have any hope of ever resolving it. There's no point at all in trying. We are much better off spending our time working with the equipment we've got to find the most obvious exosolar planets, rather than devoting an inordinate amount of effort looking at only one implausible system, driven by nothing but romantic hope.

    - Warren
  4. Feb 27, 2005 #3
    Not all romantic. Scientifically alpha centuri A and B can hold life bearing planets, proved here ---

    "In a binary system, a planet must not be located too far away from its "home" star or its orbit will be unstable. If that distance exceeds about one fifth of the closest approach of the other star, then the gravitational pull of that second star can disrupt the orbit of the planet. Recent numerical integrations, however, suggest that stable planetary orbits exist: within three AUs (four AUs for retrograde orbits) of either Alpha Centauri A or B in the plane of the binary's orbit; only as far as 0.23 AU for 90-degree inclined orbits; and beyond 70 AUs for planets circling both stars (Weigert and Holman, 1997). Hence, under optimal conditions, either Alpha Centauri A and B could hold four inner rocky planets like the Solar System: Mercury (0.4 AU), Venus (0.7 AU), Earth (1 AU) and Mars (1.5 AUs).

    Indeed, the AB system may be more than twice (1.3 to 2.3 times) as enriched in elements heavier than hydrogen ("high metallicity") than our own Solar System (Cayrel de Strobel et al, 1991, page 297; Furenlid and Meylan, 1984; and Flannery and Ayres, 1978). Hence, either stars A or B could have one or two "rocky" planets in orbital zones where liquid water is possible. "

    Above from:

    Ahad's virtual bridge already set for 2275 AD launch of first human colony:

  5. Feb 27, 2005 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    My points above stand. You can spend all the time you want dreaming about extraterrestrial life in the A Centauri system, but you're not going to convince anyone with a significant telescope to waste his or her time looking for anything there.

    - Warren
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook