The fluxuations give clues about the origin of galaxies and the large-scale structure of galaxies. It is essentially a map of temperature fluctuations across the universe left behind from the Big Bang. The very first form of light we can look back and see comes from this time and is known as the cosmic microwave background radiation. Light that previously couldn’t travel without being scattered by the dense ionized plasma of early particles could now travel freely. Credit: NASA | › Full image and caption | + Expand image The image was captured by the Wilkinson Microwave Anisotropy Probe, or WMAP, which spent nine years, from 2001 to 2010, collecting data on the early universe. This image shows the temperature fluctuations (shown as color differences) in the cosmic microwave background from a time when the universe was less than 400,000 years old. This process, known as recombination, occurred about 240,000 to 300,000 years after the Big Bang. As the universe cooled, protons and neutrons combined into ionized hydrogen and helium, which had a positive charge, and eventually attracted all those negatively charged electrons. For the first few hundred-thousand years, the universe was a hot, dense flood of protons, electrons, and neutrons, the tiny particles that make up atoms. The universe, time, and space all began about 13.8 billion years ago with the Big Bang. To better understand what the Webb telescope will study, it’s helpful to know what happened in the early universe, before the first stars formed. What the first galaxies looked like and when they formed is not known, and the Webb telescope is designed to help scientists learn more about that early period of the universe. "The last few months have been exciting, but a huge amount remains in front of us to learn.A look at the James Webb Space Telescope, its mission and the incredible technological challenge this mission presents. "We can see that we're really on track to realizing the dream of understanding galaxies at the earliest times," says Illingworth. "It's exciting for us, from a theoretical standpoint, that maybe there are some open questions about how these galaxies could have formed their stars so much earlier that we're able to detect large numbers of them," says Jeyhan Kartaltepe of the Rochester Institute of Technology.įinding galaxies like these, and building a greater understanding of how the universe evolved to be what it is today, is why astronomers spent decades and $10 billion dollars to design and launch JWST. The two newly-seen galaxies are both much smaller that our home galaxy, the Milky Way, and one appears to be unexpectedly elongated.īecause so many early, bright galaxies have been seen by JWST, astronomers are having to rethink their old ideas about the evolution of the universe. "There's certainly a lot of discussion going on." "We feel very confident about these two, but less confident about the others," says Illingworth. But those are more tentative observations. Since astronomers started using JWST, some have claimed to have spotted galaxies from even earlier times, like 250 million years after the Big Bang. That latter discovery broke a record set by the Hubble Space Telescope in 2016, when it managed to glimpse a galaxy called GN-z11, which existed about 400 million years after the Big Bang.Īstronomer Garth Illingworth of the University of California, Santa Cruz was a member of the team that found GN-z11, and says that seeing it was "a huge surprise." But now, with the help of their new space telescope, scientists know it wasn't just a weird outlier - because they have at least two more examples. In research papers published in The Astrophysical Journal Letters, Treu and other astronomers report the discovery of one galaxy that dates back to just 450 million years after the beginning, and another that dates back to 350 million years. "JWST has opened up a new frontier, bringing us closer to understanding how it all began." "Just a few hundred million years after the Big Bang, there are already lots of galaxies," says Tommaso Treu, an astronomer at the University of California at Los Angeles.
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