The light of this event left its source billions of years before the Earth existed!

Long before it became the luminous spiral galaxy we call home, the Milky Way was a sprawling, chaotic swarm of thousands of small galaxies, new research shows.The findings suggest that in the first 2 billion years after the Big Bang, the region of the universe that would become our galaxy was littered with thousands of smaller galaxies of many sizes and shapes. Over time, these galaxies collided and merged into the single galaxy in which we reside today."Looking at these results, it's very clear that the physics happening right after the Big Bang has direct impact on what we see today in the local universe," study co-author Harley Katz, an assistant professor of astronomy and astrophysics at the University of Chicago, said in a statement. To understand more about the early universe, astronomers build sophisticated computer models that encode the laws of nature to see how the cosmos may have evolved. The new work, which is the result of three years of supercomputer simulations, is the most detailed tracing yet of how a galaxy like ours came to be. It also arrives just as astronomers need a stronger yardstick for what they're seeing in the early universe. Megatron, the cosmic transformerThe James Webb Space Telescope (JWST) can peer farther into the early universe than any previous telescope, and its discoveries have often defied computer models. For instance, JWST found surprisingly bright early galaxies and a mysterious new class of compact galaxies dubbed "Little Red Dots." These anomalies demonstrate that current computer models need an update to handle the complex physics of the early universe, the researchers said.To bridge that gap, the scientists built a new suite of supercomputer simulations they call Megatron. By tracing ancient gas, starlight and chemistry from 180 million years to 2 billion years after the Big Bang, Megatron predicts the distinct light signatures of its virtual galaxies, according to the statement. Because JWST collects the same type of spectral data across a similar span of cosmic time, scientists can directly cross-reference the simulation against real observations to pinpoint what the old models are missing, the team said.The simulation also tracks how the universe's first stars formed, died and forged the essential elements that make life as we know it possible. By comparing the simulation with JWST observations of early galaxies and with the chemical traces left in ancient stars, scientists can better understand how those first stars enriched their surroundings, the researchers said."Together, these complementary observations allow us to test competing models of the first stars in ways that weren't previously possible," study co-author Martin Rey, a theoretical astrophysicist at the University of Bath in the U.K., said in a separate statement.The scientists detailed their findings in one of the six papers the Megatron collaboration published Sept. 30 in The Open Journal of Astrophysics.Assembling the Milky WayThe team's simulation begins 180 million years after the Big Bang, when the universe is devoid of stars and galaxies and holds only pristine gas. As the next 2 billion years pass,, the model captures how the very first stars light up the dark universe and kick off "cosmic dawn," eventually culminating in those stars' violent deaths. As they die, the stars spread newly forged heavy elements such as carbon, oxygen and iron into the surrounding gas, laying the building blocks for future stars and planets.A simulated view of what the Milky Way may have looked like 12 billion years ago. The bands of light are remnants of a galaxy collision, one of the thousands of mergers that the new study says built our galaxy. (Image credit: Harley Katz/MEGATRON Collaboration)The simulation ends 2 billion years after the Big Bang, but the Milky Way's mergers continued long after this point, and scientists are still discovering traces of the small galaxies that have joined it. The most recent massive merger, with the Sagittarius dwarf galaxy, began more than 6 billion years ago and is still unfolding.Related stories'Astronomers have to revise estimates': The Milky Way may be larger, heavier and more lopsided than we realizedHow did the Milky Way form?Astronomers find water in the harsh environment near the Milky Way's black hole — Space photo of the weekThe simulation results help scientists understand how certain physics parameters impact the early universe, and better match up JWST's observations with computer models. But it also highlights areas that need further study. "But there are also things we're not getting right, which is interesting too — what are the parts we're still missing?" Katz said in the statement. "That can lead you into new directions and new questions."Megatron team members in the U.K. are now developing the next generation of simulations, backed by dedicated time on the country's supercomputers. Those simulations will include more complex physics, such as active black holes, which JWST has revealed to be surprisingly common in the early universe, the researchers said.How well do you know our home galaxy? Find out with our Milky Way quiz!

Astronomers have detected the most distant burst of radio signals ever seen: an explosion that's emitting waves of energy from more than 10 billion light-years away.The event, named FRB 20240304B, is known as a fast radio burst (FRB). Astronomers have detected thousands of FRBs before this. But because these events last only milliseconds, they are extremely difficult to study and their origin stories remain unclear.In this case, however, astronomers managed to use a radio telescope array and the James Webb Space Telescope (JWST) to chart the event, with JWST narrowing down the precise host galaxy that FRB 20240304B came from. The study, published Thursday (Oct. 8) in the journal Science , sheds more light on a time when the universe was only about 3 billion years old, showing that FRBs arose early in our cosmos' history. The detection more than doubles the previous distance record for FRBs.The JWST played an instrumental role in the discovery, study co-author Themiya Nanayakkara, a senior lecturer at the Sydney Institute for Astronomy, told Live Science in an email. The email was written in collaboration with study first author Manisha Caleb, a senior lecturer in astrophysics at the same university. For example, JWST's observations showed that the host galaxy was smaller than expected, was "metal-poor" (had few elements besides hydrogen and helium), and was forming a lot of stars. These characteristics could offer new clues about the environments in which FRBs arise, giving more information about the mysterious events. Researchers suggest that this FRB may have been linked to a magnetar, a highly magnetic star core left after a supernova.Zooming in with the James Webb telescopeThe ancient FRB was initially detected with MeerKAT, an array of 64 radio telescopes in South Africa. Nanayakkara said MeerKAT revealed "both the detection of the fast radio burst and, importantly, a very precise position on the sky."The researchers knew the FRB was far away because of the large dispersion of the radio signal, but initial searches with powerful ground-based telescopes, "saw essentially nothing; it looked like empty sky," the researchers told Live Science. "The most likely explanation was that the galaxy was simply too faint to be detected in those observations. That is where JWST became transformative."An illustration of a fast radio burst (FRB) being detected by the MeerKAT radio telescope array. (Image credit: Carl Knox - OzGrav, Swinburne University of Technology Background Image Credit: NASA, ESA, CSA, STScI, Themiya Nanayakkara (USYD) Background Image Processing Credit: Joseph DePasquale (STScI))The science team successfully got time on JWST with a program called Director’s Discretionary Time, which is aimed at time-sensitive observations. The researchers started by using JWST's Near Infrared Camera to trace the radio signal and take a very deep image of the target region. "Suddenly, there it was: a very faint galaxy almost exactly where we expected the host of the FRB to be," Nanayakkara said. The researchers then used JWST's Near Infrared Spectrograph to obtain a spectrum (wavelengths of light broken into different chemical signatures), which showed hydrogen and oxygen."These spectral features act like fingerprints: because we know the wavelengths at which they are produced in the laboratory, we can measure how much they have been shifted by the expansion of the universe," Nanayakkara explained. "That gave us a very precise redshift of about 2.15. We are therefore seeing this galaxy as it was when the universe was only around three billion years old, so roughly one-fifth of its current age."Related storiesWhere do fast radio bursts come from? Astronomers tie mysterious eruptions to massive galaxies.Mysterious deep-space flashes repeat every 157 daysFast radio burst traced to the outskirts of an ancient 'graveyard' galaxy — and the cause remains a mysteryBecause the host galaxy is fairly young, it supports the idea that at least some FRBs are generated by magnetars, which are more likely to appear in spry galaxies where intense star formation is occurring, the team said. The team plans to continue hunting for FRBs with JWST. "We do not know what the sources will be yet," Nanayakkara said, as that depends on what pops up in the sky and is spotted by ground-based radio telescopes. "Once our radio telescopes find and localize a suitable new source, we can trigger the JWST observations. So it is quite exciting, because we really have no idea what we will find when we combine the power of these two types of telescopes."

Scientists have recently harnessed artificial intelligence (AI) to build "aging clocks" that aim to estimate a person's true biological age. While a person's chronological age reflects the number of years they've been alive, their biological age is intended to capture how well their bodily systems are functioning. The idea is that people with older biological ages have a higher risk of age-related diseases ‪—‬ such as cancer, heart disease or dementia ‪—‬ while younger biological ages come with less risk. Some aging clocks even aim to predict people's impending risk of death.Related storiesSped-up 'biological aging' linked to worse memoryAging doesn't look the same for everyone at the molecular level — it's 'individualized and context-dependent''We can identify these really early, before the clinical diagnosis': Epigenetic markers may help explain why Native Hawaiians are aging fasterMany aging clocks look at epigenetic markers, meaning chemical tags that bind DNA and change how genes activate, while others measure features such as the pace and pitch of people's voices. But some scientists say we don't know how to use these aging clocks yet, arguing that the tools are useful for studying aging at a population level but not for guiding individual health decisions. Others posit that the data the clocks are based on is too noisy, and thus, there's potential for drawing faulty conclusions about what they're measuring. They say, for example, that we don't know if the clocks are measuring the downstream effects of aging or its underlying causes. And in any case, we don't currently have any treatments to "wind back" the clocks.What do you think? Would you use these AI tools to measure your biological age? Let us know in the poll below, and explain your reasoning and additional thoughts about the technology in the comments.

Neutrinos are persnickety particles. We couldn't really detect neutrinos from deep space until Francis Halzen had a brilliant, Nobel Prize-winning idea.