Hubble Accidentally Discovers An Ancient, Nearby Dwarf Galaxy

By Korey Haynes | February 1, 2019 4:30 pm
a field of bright stars with dwarf galaxy Bedin 1 circled at lower left

Astronomers used the Hubble Space Telescope to discover dwarf galaxy Bedin 1 (lower left) by accident while studying the bright cluster stars in front of it. (Credit: NASA/ESA/L. Bedin)

The Hubble Space Telescope has discovered a small and strangely isolated dwarf galaxy just 30 million light-years away from our own Milky Way. And astronomers say the discovery was completely by accident.

Luigi Bedin, of the Astronomical Observatory of Padua, and his colleagues were using Hubble to study a globular star cluster called NGC 6752. Globular clusters are tightly packed crowds of ancient stars. And when they looked at the images Hubble sent back, they noticed a small galaxy hiding behind the cluster’s brighter stars.

Dwarf Galaxy is a Hermit

The galaxy, dubbed Bedin 1 by its discoverer, is distinct in its isolation. There’s a chance this small swirl of stars may be connected to a larger nearby galaxy, but the two are far apart and it’s not clear they have ever interacted. And that’s what makes Bedin 1 so interesting for astronomers. First, most dwarf galaxies are found huddled up closer to a larger galaxy. Second, Bedin 1 shows little sign of past interactions with any galactic neighbors.

Dwarf galaxies are common in the universe, but most ride the coattails of larger galaxies. Because regular galaxies like the Milky Way are hundreds or even thousands of times larger, these dwarf galaxies are at the gravitational mercy of their larger brethren. Astronomers have often noted evidence of smaller galaxies being pulled apart or consumed by larger ones. And all this activity can often mean complex histories of star formation, as old stars get ripped away and gas – the fuel of starbirth – gets pushed around, sparking new generations of stars.

When galaxies make stars, they tend to do so in batches that include all types at once: giant stars that burn hot and die quickly, and small stars that live longer than the universe’s lifespan so far. Nearly all the stars astronomers measured in Bedin 1 are small and old, implying the dwarf galaxy made all its stars in a single burst of activity some 10 billion years ago. Bedin 1 has sat quietly ever since, letting its massive stars burn out and die and making no new stars to replace them, unperturbed by the cosmic shuffle around it.

So if Bedin 1 is gravitationally connected to the distant NGC 6744, the larger galaxy appears to have left its little sibling alone.

The astronomers also note that a survey planned for the upcoming Wide Field Infrared Survey Telescope (WFIRST, planned to launch in the mid-2020’s) may find more of these small, hermit-like galaxies.

The team published their discovery Jan. 31, in the Monthly Notices of the Royal Astronomical Society: Letters.

CATEGORIZED UNDER: Space & Physics, top posts
  • Erik Bosma

    Could Bedin 1 have been an ancient star cluster from the second generation of star formation – the first could have been the large stars that are now the black holes around which the star clusters formed – which collided with another ancient star cluster to form this small rogue galaxy. This collision would have then ignited all the remaining gas contained within these 2 clusters.
    Amazing how it never had another collision after this initial one. Or perhaps it’s not so amazing and the universe may contain many millions or billions of these mini-galaxies. Hmmm…

    • Mach1Airspace

      Runaway grey matter, dude! It’s too old 10/12B yrs) to be Gen2, almost assuredly Gen1, plus no black holes at center of clusters, only at galaxy core :)

  • TefferMcG

    So it’s deserted

  • Hoplite99

    Perfect place to exile Team Trump to.

    • Victoria

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    • Bob Kaczynski


      • StanChaz

        Yes they are, indeed.

    • Lorie Franceschi

      Science article, don’t make political. Idiotic moron.

  • tom

    I believe Bedin is part of the Collective.

  • Scott Wortherman

    Why do young and old spiral galaxies look similar?

    Both nearby galaxies and the faraway ones show the same sort of spiral structure.

    The nearby galaxies should not be spirals anymore, because in the time that is supposed to have elapsed, they should have wound themselves up long ago, blurring the spiral appearance.

    These recently-observed galaxies are ultra-young (according to ‘big bang’ belief) because they are so far away. So they should not have had time to develop even the beginnings of a spiral.

    • Aggressive Progressive

      The Big Bang is a scientific theory with overwhelming evidence, not a belief. Publish your evidence falsifying it if you have any.

      • Scott Wortherman

        What was there for the Big Bang to ‘bang’?

        • Aggressive Progressive

          Where were you before you were conceived?

          • Scott Wortherman

            I am the result of pre-existing biological organisms coming together to form a new life. What was there for the Big Bang to ‘bang’?

          • Aggressive Progressive

            The Big Bang is the result of pre-existing cosmological conditions coming together to form another universe in an eternally expanding multiverse. That’s what was there for the Big Bang to ‘bang.’

          • Scott Wortherman

            Ah. I see. Two things …

            Where did those “pre-existing cosmological conditions” come from?

            If the “eternally expanding multiverse” is indeed eternal then there is no way to measure age because being eternal means ageless.

          • Aggressive Progressive

            Good questions. (Don’t you love when you’re complimented on your questions?)

            All seriousness aside, you also hint at the idea of the Anthropic Principle. Why is there “something,” “anything,” rather than “nothing,” and what is “nothing”?

            We exist in this particular observable and measurable universe because if it weren’t observable and measurable as it is we wouldn’t be here to observe and measure it.

            My favorite question is, given what we know about this universe now, if we used the same bits, sort of like Legos, how many other universes could we build with the those parts? The most recent calculation is around 10^500 before we would need another box.

            Compared to the reality of infinite space and eternal time, however, that’s “nothing.”

          • Scott Wortherman

            Nothing is *NO THING*. It is what rocks dream of.

            Since we live in a universe that is observable and also measurable, it cannot be infinite … infinite cannot be measured. So there is no ‘reality’ of an infinite space.

            I ask again … Where did those “pre-existing cosmological conditions” come from?

          • Aggressive Progressive

            It emerges from space-time, which is not a thing and therefore nothing. Our universe is finite, the multiverse in which it resides is infinite. It is an explanation that requires imagination, and not an “answer.”

          • Scott Wortherman

            So material particles emerge from space-time?

          • Aggressive Progressive

            It appears so. Quantum Gravity (the best proposed theory/explanation at the moment along with String Theory,) seems to emerge with the wave-function collapse at the Planck scale to form the proposed graviton at the BB and the emergence of the strong, weak, and electromagnetic forces which produce elemental hydrogen, helium, a little bit of lithium and all the energy we see today. As Richard Feynman said, Quantum Mechanics is wielder than you can imagine.

          • Scott Wortherman

            Nice theory. Space needs somewhere to be put and time needs somewhere to start. And gravity is a force that requires something to cause it. Nothing can do any of this.

            If you want to believe that nothing created everything when our universe clearly shows that everything material has a material cause then go ahead. I don’t have enough faith for that.

          • Aggressive Progressive

            If you must resort to faith and belief, then the conversation is over.

          • Scott Wortherman

            It is your faith in that everything comes from nothing that I cannot adopt. It all starts from that.


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