1/1/2023 0 Comments High powered telescope![]() But I think the scientific questions it may help answer will be worth every ounce of effort. James Webb is the most technically difficult mission NASA has ever attempted. For example, unraveling this story may also help explain the nature of dark matter, the mysterious form of matter that makes up about 80% of the mass of the universe. With this data, it may be possible to answer when and how the Dark Ages ended, but there are many other important discoveries to be made. #High powered telescope PatchThe strategy will be to stare deeply at one patch of sky for a long time, collecting as much light and information from the most distant and oldest galaxies as possible. Compared to the Hubble Space Telescope, James Webb has a 15 times wider field of view on its camera, collects six times more light and its sensors are tuned to be most sensitive to infrared light. So the further out in space astronomers look, the further back in time we are looking.Įngineers optimized James Webb for specifically detecting the faint infrared light of the earliest stars or galaxies. If an object is 10,000 light-years away, that means the light takes 10,000 years to reach Earth. The James Webb Space Telescope was specifically designed to detect the oldest galaxies in the universe. To see first light, you have to be looking for infrared light. It arrives as infrared light, meaning it has a wavelength longer than that of red light. Though not a perfect analogy, it is similar to how when a car drives past you, the pitch of any sounds it is making drops noticeably.īy the time light emitted by an early star or galaxy 13 billion years ago reaches any telescope on Earth, it has been stretched by a factor of 10 by the expansion of the universe. ![]() This is called redshift because it shifts light of shorter wavelengths-like blue or white light-to longer wavelengths like red or infrared light. This early light is very faint by the time it gets to Earth.Īs the universe expands, it continuously stretches the wavelength of light traveling through it. It took several hundred million years for radiation to blast away the fog. Also, the earliest stars were surrounded by gas left over from their formation and this gas acted like fog that absorbed most of the light. Compared to massive, bright galaxies of today, the first objects were very small and due to the constant expansion of the universe, they're now tens of billions of light years away from Earth. They burned hot and bright and when they died, they left behind black holes up to a hundred times the Sun's mass, which might have acted as the seeds for galaxy formation.Īstronomers would love to study this fascinating and important era of the universe, but detecting first light is incredibly challenging. They were a million times brighter but they lived very short lives. ![]() These first stars in the universe were extreme objects compared to stars of today. ![]() ![]() Credit: Inductiveload/NASA via Wikimedia Commons, CC BY-SAĬurrent theories based on how gravity forms structure in a universe dominated by dark matter suggest that small objects-like stars and star clusters-likely formed first and then later grew into dwarf galaxies and then larger galaxies like the Milky Way. Light from the early universe is in the infrared wavelength – meaning longer than red light – when it reaches Earth. If anyone had been there to see it at this point, the universe would have been glowing dull red like a giant heat lamp. Around 400,000 years after the Big Bang, the universe was 10 million light years across and the temperature had cooled to 5,500 F (3,000 C). One second after the Big Bang, the universe was a hundred trillion miles across with an average temperature of an incredible 18 billion F (10 billion C). The universe immediately began expanding after the Big Bang, cooling as it did so. When did the first stars and galaxies form? Which came first, and why? I am incredibly excited that astronomers may soon uncover the story of how galaxies started because James Webb was built specifically to answer these very questions.Įxcellent evidence shows that the universe started with an event called the Big Bang 13.8 billion years ago, which left it in an ultra-hot, ultra-dense state. Some of the biggest unanswered questions about the universe relate to its early years just after the Big Bang. I'm an astronomer with a specialty in observational cosmology-I've been studying distant galaxies for 30 years. ![]()
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