Exoplanet anniversary: 1st alien worlds confirmed 25 years ago today

Posted: January 9, 2017 by oldbrew in Astronomy, exploration, History

Still from pulsar animation.  [Image credit: NASA]

Still from pulsar animation. [Image credit: NASA]

The exoplanet revolution began 25 years ago today. On Jan. 9, 1992, astronomers Alex Wolszczan and Dale Frail published a paper in the journal Nature announcing the discovery of two planets circling an incredibly dense, rapidly rotating stellar corpse known as a pulsar.

It was a landmark find: while several alien-world “candidates” had recently been spotted, Wolszczan and Frail provided the first confirmation that planets exist beyond our own solar system, reports Mike Wall.

“From the very start, the existence of such a system carried with it a prediction that planets around other stars must be common, and that they may exist in a wide variety of architectures, which would be impossible to anticipate on the basis of our knowledge of the solar system alone,” Wolszczan, who’s based at Pennsylvania State University, wrote in a note about the pulsar planets for the “Name Exoworlds” contest sponsored by the International Astronomical Union.

The pulsar, called PSR B1257+12, lies about 2,300 light-years away from Earth, in the constellation Virgo. The two history-making planets, which Wolszczan and Frail detected using the Arecibo Observatory in Puerto Rico, are both about four times as massive as Earth. One takes 66 days to complete one lap around the pulsar, while the other’s orbital period is 98 days.

Wolszczan and his colleague Maciej Konacki found a third planet orbiting the same pulsar in 1994. This world, which has a period of 25 days, is the least massive exoplanet known; it’s just twice as hefty as Earth’s moon.
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The pace of discovery skyrocketed after the launch of NASA’s Kepler space telescope in March 2009. Kepler detects exoplanets by noting the tiny brightness dips that orbiting planets cause when they cross their hosts stars’ faces from the spacecraft’s perspective. To date, Kepler has found 2,330 confirmed alien worlds using this “transit method” — about two-thirds of the 3,500-odd exoplanets known.

Kepler’s observations also suggest that, on average, every star in the Milky Way galaxy hosts at least one planet. Furthermore, a sizable percentage of these trillion or so worlds are likely in their star’s “habitable zone” — the just-right range of distances where liquid water could exist on a planet’s surface.

So now, just a quarter-century after exoplanet science got its start, astronomers are racing to make epochal discoveries in the field — the first true “alien Earth,” and, perhaps, evidence that our planet is not the only one that supports life.

Full report: Exoplanet Anniversary: 1st Alien Worlds Confirmed 25 Years Ago Today | Space.com

Talkshop note – Wikipedia says: ‘The discovery stimulated a search for planets orbiting other pulsars, but it turned out such planets are rare; only one other pulsar planet, orbiting PSR B1620-26, has been confirmed.’

  1. oldbrew says:

    Astronomers predict explosion that will change the night sky in 2022
    January 9, 2017 by Matt Kucinski, Lynn Rosendale

    Molnar’s prediction is that a binary star (two stars orbiting each other) he is monitoring will merge and explode in 2022, give or take a year; at which time the star will increase its brightness ten thousand fold, becoming one of the brighter stars in the heavens for a time. The star will be visible as part of the constellation Cygnus, and will add a star to the recognizable Northern Cross star pattern.

    Read more at: http://phys.org/news/2017-01-astronomers-explosion-night-sky.html

  2. linneamogren says:

    The Science Channel reported a year ago that most scientists no longer believe life sprung from earth but rather arrived to earth. I’ve always thought this kicks the cosmic can down the road. If we can’t assume any longer life arose from earth what other conditions could exist in these other worlds to create life even they too most likely have sun water and oxygen

  3. oldbrew says:

    LM: are you sure it was the Science Channel 😉

    They Came From Somewhere Else

  4. oldbrew says:

    Report: Mysterious Planet Nine May Be a Captured ‘Rogue’ World

    Planet Nine may be even more exotic than astronomers had thought.

    The putative world, which some scientists think lurks unseen far beyond Pluto’s orbit, could be a former “rogue planet” that was captured by our solar system at some point in the past, a new study suggests.

    “It is very plausible” that Planet Nine is a captured rogue — a world that cruises through space unattached to a star — lead author James Vesper, an undergraduate at New Mexico State University (NMSU), said Friday (Jan. 6) during a news conference at the 229th meeting of the American Astronomical Society in Grapevine, Texas.

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    Still ‘putative’ though.

  5. linneamogren says:


    Yes it was the Science Channel, I was watching a show about multiverses and it came on after it.

    If life arose on earth they believe the odds were very much against such a process. RNA is very complex and the likelihood it just developed was unlikely in their opinion. Now we could assume RNA evolved from more simpler process of molecules or less complex chemistry. But less complex is subjective at best and pure conjecture.

    The chance of one self-replicating peptide only 32 amino acids long is 10^40 and anything over 10^50 is considered not probable. Moving to the complexities of DNA odds become ridiculous.

    Dawkins and other scientists believe the odds are too great unless there are a billion billion planets and universes which would then allow for immense chances on the roll of a dice.

  6. p.g.sharrow says:

    Ours is a 3rd generation star so this “interloper” might well be a planet from a former life.
    although I would suspect it is quite large, Brown Dwarf size. Disruptions of our solar planetary system show at least 3 close encounters with some thing LARGE.

    As to the creation of life, it may well be inevitable. NOx is a self replicating molecule that grows into long strands. as long as the energy levels in the oxygen and nitrogen soup remain at the right levels. Hydrocarbons do the same thing at lower energy levels.
    Until some thing starts eating the soup to create more of it’s “kind” the soup would just accumulate. the RNA and DNA we are famular with are just the strongest survivors. Most of the volumn of life on this planet is single cell and exists to great depth in the crust. This life may well have orignated under the conditions of the preEarth/Luna small Gas Giant …pg

  7. linneamogren says:

    Single cells are far from simple and even their chance of spontaneous creation is astronomical. The biggest problem one has to overcome in this field is how can meaningful genetic sequencing occur before there’s meaningful genetic information? So where did meaningful genetic info come from? This is why Dawkins and others assume its unearthly and others assume God.