Slashdot Mirror

← Back to Stories (view on slashdot.org)

Hubble Space Telescope Spots the Farthest Known Star (engadget.com)

Posted by BeauHD on from the record-breaking dept.

Researchers using Hubble space telescope data have spotted Icarus (aka MACS J1149+2223 Lensed Star 1), a blue supergiant whose light was emitted when it was 9 billion light years away from Earth -- over 100 times farther than the previous record-setter. According to Engadget, "They captured the star thanks to a rare, ideal gravitational lensing effect where the star's light was magnified not only by the gravity of an in-between galaxy cluster 5 billion light years from Earth, but by a star inside that cluster." From the report: Observers had been keeping close watch on the cluster since 2014, when they'd detected a supernova that turned out to be present in a galaxy 9 billion light years away. They realized Icarus was present in April 2016, when a point of light near the supernova seemed to change brightness. Don't get too attached to this new discovery. With this kind of distance, Icarus has long-since turned into a neutron star or black hole. The findings are still advancing science in ways you might not expect, however. As the Guardian noted, the Icarus study ruled out a theory that dark matter consists of black holes. If that had been the case, they would have brightened Icarus even more. And if nothing else, this proves that humanity can detect more than just the largest and brightest celestial objects at these kinds of distances.

5 of 74 comments (clear)

  1. The Hubble saw _THAT_?! by Pezbian · · Score: 4, Insightful

    If that old thing can see something so unique and far away, I can only imagine what the James Webb Space Telescope is ultimately capable of.

    If it ever launches.

    --
    In a world of the blind, the one-eyed man is king--and the two-eyed man is a heretic.
    1. Re:The Hubble saw _THAT_?! by Gavagai80 · · Score: 5, Insightful

      The Hubble isn't the telescope doing 99% of the magnification work here. The galaxy cluster and the star within are the two powerful telescopes being used.

      --
      This space intentionally left blank
    2. Re:The Hubble saw _THAT_?! by jfdavis668 · · Score: 4, Informative

      They use the light of type Ia supernovas, which explode with a know brightness, to determine the distance to a galaxy. Then they compare that to its redshift so determine the redshift to distance ratio. Then, all you need to do is measure the object's redshift to determine its distance.

    3. Re:The Hubble saw _THAT_?! by stevelinton · · Score: 4, Interesting

      If that old thing can see something so unique and far away

      I still don't understand how they can determine distances of such far-out objects. Yes I am aware of standard candles, and that we "know" how far away they are based on observed brightness. But observed brightness isn't just impacted by distance, it is also impacted by the size of the object. So how can we be so sure that these standard candles are not bigger or smaller than we assume they are?

      Are the distances simply so large, that a standard candle would need to be exponentially larger/smaller than our assumed size in order to significantly impact the calculated distance?

      Standard candles are things that have a fixed total brightness (or at least a brightness that we can work out independent of their size).

      For instance a certain type of supernova is believed to happen when a white dwarf star, slowly accreting matter from a companion, finally gets too massive to support itself and collapses into a neutron star. Regardless of the mass of the original white dwarf, this mass at which this collapse happens is pretty much the same, and so the total brightness of this type of supernova is more or less constant.

  2. Re:No grav lensing by jfdavis668 · · Score: 4, Informative

    Space is bent by gravity, not light. Light then takes the shortest path through the curved space time.