Shockingly young galaxy surprises scientists with its impressive bulge

By Elizabeth Howell
published

Peering into the early universe, astronomers uncovered a surprise: a young galaxy that looks a lot like our home, the Milky Way.

The newfound galaxy is called SPT0418-47 and, given its great distance from Earth, astronomers see the galaxy as it was when the universe was just 1.4 billion years old — roughly 12 billion years before today.

The discovery held a big surprise for the researchers. Stars were forming quickly, as expected, since there was abundant gas available when the universe was young. But despite the chaos, SPT0418-47 had a well-defined, rotating disk and galactic "bulge" at the center. That's a similar structure to the Milky Way's today; moreover, the observed bulge is the most distant ever found in our universe.

Related: How galaxies are classified by type (infographic)

A gravitationally lensed view of a ring-shaped slice of a galaxy called SPT0418-47, as seen by the ALMA array in Chile. (Image credit: ALMA (ESO/NAOJ/NRAO), Rizzo et al.)

Analogies between SPT0418-47 and the Milky Way are not perfect, however. The Milky Way sports a distinctive barred-spiral shape, formed by large "arms" of stars and gas. But SPT0418-47 lacks such arms; moreover, scientists expect it will evolve into another galaxy type entirely, an elliptical galaxy. 

Yet the newfound galaxy does give insight into the evolution of these massive star-filled structures over the eons. Based on this new find, it appears there may have been less dramatic galaxy change than previously imagined.

"The structures that we observe in nearby spiral galaxies and in our Milky Way were already in place 12 billion years ago," lead author Francesca Rizzo, a Ph.D. student from Germany's Max Planck Institute for Astrophysics in Germany, said in a statement from the European Southern Observatory (ESO).

A reconstruction of the full SPT0418-47 galaxy. (Image credit: ALMA (ESO/NAOJ/NRAO), Rizzo et al.)

It was the powerful Atacama Large Millimeter/submillimeter Array (ALMA) that allowed astronomers to spy on SPT0418-47. ALMA consists of 66 antennas scattered across the Chilean desert, working together to create one large telescopic lens. The newfound galaxy was too faint to be observed directly, so ALMA used a technique called "gravitational lensing" to overcome the problem, magnifying SPT0418-47's light using the gravity of a nearby galaxy.

Gravitational lensing can produce some distortion, but in this case, the alignment between the two galaxies was almost exact, according to the statement. This makes SPT0418-47 appear as a nearly perfect ring in the raw images. Researchers found the true shape and gas motion of the galaxy using a new computer model.

Future telescopes, such as ESO's Extremely Large Telescope, will peer further into the early universe to better figure out how common SPT0418-47's shape was among the galactic population of the era.

A study based on the research was published on Wednesday (Aug. 12) in the journal Nature.

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Elizabeth Howell
Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 covering diversity, education and gaming as well. She was contributing writer for Space.com for 10 years before joining full-time. Elizabeth's reporting includes multiple exclusives with the White House and Office of the Vice-President of the United States, an exclusive conversation with aspiring space tourist (and NSYNC bassist) Lance Bass, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?", is co-written with astronaut Dave Williams. Elizabeth holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and a Bachelor of History from Canada's Athabasca University. Elizabeth is also a post-secondary instructor in communications and science at several institutions since 2015; her experience includes developing and teaching an astronomy course at Canada's Algonquin College (with Indigenous content as well) to more than 1,000 students since 2020. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday. Mastodon: https://qoto.org/@howellspace

7 Comments Comment from the forums
  • voidpotentialenergy
    I get the same remark all the time :)
    Reply
  • rod
    The article says "The discovery held a big surprise for the researchers. Stars were forming quickly, as expected, since there was abundant gas available when the universe was young."

    My observation. Looks this galaxy contradicts or conflicts with LCDM model expectations in BB cosmology. It should be interesting to follow cosmology reports on this galaxy, SPT0418-47.

    https://www.nature.com/articles/s41586-020-2572-6, "Abstract The extreme astrophysical processes and conditions that characterize the early Universe are expected to result in young galaxies that are dynamically different from those observed today1,2,3,4,5. This is because the strong effects associated with galaxy mergers and supernova explosions would lead to most young star-forming galaxies being dynamically hot, chaotic and strongly unstable1,2. Here we report the presence of a dynamically cold, but highly star-forming, rotating disk in a galaxy at redshift6 z = 4.2, when the Universe was just 1.4 billion years old. Galaxy SPT–S J041839–4751.9 is strongly gravitationally lensed by a foreground galaxy at z = 0.263, and it is a typical dusty starburst, with global star-forming7 and dust properties8 that are in agreement with current numerical simulations9 and observations10. Interferometric imaging at a spatial resolution of about 60 parsecs reveals a ratio of rotational to random motions of 9.7 ± 0.4, which is at least four times larger than that expected from any galaxy evolution model at this epoch1,2,3,4,5 but similar to the ratios of spiral galaxies in the local Universe11. We derive a rotation curve with the typical shape of nearby massive spiral galaxies, which demonstrates that at least some young galaxies are dynamically akin to those observed in the local Universe, and only weakly affected by extreme physical processes."
    Reply
  • Torbjorn Larsson
    rod said:

    The article says "The discovery held a big surprise for the researchers. Stars were forming quickly, as expected, since there was abundant gas available when the universe was young."

    Looks this galaxy contradicts or conflicts with LCDM model expectations in BB cosmology.

    I think you got the quote wrong, it isn't the star formation that is unexpected, it is the balance between rotational and random redshift distribution - as well as the bar - that reminds of nearby galaxies.

    I'm not sure if they can model galaxy development on that scale in cosmological simulations due to lack of resources. IIRC the latest plaint was that they can't put model the super massive black holes and gas feedback that we know are active in galaxy development. This is, or was, the research edge 2 years ago:

    Perhaps the simulations' single biggest lesson so far is not that scientists need to revise their overarching theory of cosmology, but rather that problems lurk in their understanding of astrophysics at smaller scales. In particular, their theory of star formation comes up wanting,

    http://www.sciencemag.org/news/2018/05/galaxy-simulations-are-last-matching-reality-and-producing-surprising-insights-cosmic ]
    Unless I'm mistaken, I would say on the cosmological claim: "References missing."
    I don't think we can extract a conflict with current cosmology from this. In fact, I believe that train left the station 2 years ago. And that it is unlikely to "backtrack". 😀

    The one remaining data conflict is a tendency between low-z expansion observations and high-z integrative data compilations to have a > 3 sigma tension between expansion rates. Here the train is still in the station, but the most likely explanation is that it's experimental problems. We can for instance completely convert that rate tension to a tension in cosmic background radiation temperature. And that simple hypothesis has not yet been rejected.
    Reply
  • Helio
    I doubt there's any doubt regarding early galactic morphology on the whole. Isn't there a rule that there are exceptions to the rules?

    That is a heck of a nice ring!

    Perhaps DM plays a role in this earlier period, allowing a few to mature quicker. Or, perhaps we aren't seeing just one galaxy, though this seems unlikely. It was noted that no spirals seem to exist, so it's still a youngster.
    Reply
  • rod
    FYI, here is a reference indicating in cosmology, galaxy formation problems remain. 'ALMA sees most distant Milky Way look-alike', https://phys.org/news/2020-08-alma-distant-milky-look-alike.html
    "Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA), in which the European Southern Observatory (ESO) is a partner, have revealed an extremely distant and therefore very young galaxy that looks surprisingly like our Milky Way. The galaxy is so far away its light has taken more than 12 billion years to reach us: we see it as it was when the Universe was just 1.4 billion years old. It is also surprisingly unchaotic, contradicting theories that all galaxies in the early Universe were turbulent and unstable. This unexpected discovery challenges our understanding of how galaxies form, giving new insights into the past of our Universe."

    The report is about SPT0418-47, same as the space.com article. When folks read cosmology reports that use language like *surprising, unexpected*, there are indeed problems in LCDM cosmology.
    Reply
  • Helio
    rod said:
    The report is about SPT0418-47, same as the space.com article. When folks read cosmology reports that use language like *surprising, unexpected*, there are indeed problems in LCDM cosmology.
    Usually if something demonstrably challenges mainstream science, the authors likely get a little more exuberant as shattering the old to forge a path for the new is what Nobel Prizes are for. The fuzzy result they have seems interesting. The Einstein lens effect is still new but the more it is used, especially with the larger scopes that are coming soon, the more we will learn about the early universe. It would be disappointing if the early universe doesn't have surprises. Just look how everybody thought Pluto was just a cold dog, but it is a dynamic and wonderous dwarf planet instead.
    Reply
  • Lovethrust
    voidpotentialenergy said:
    I get the same remark all the time :)
    Reply