There may be other civilizations out there, but they are too distant for us to discover. To give you an idea, the James Webb Space Telescope has discovered what will be the oldest galaxy ever imaged. It is so far away that it takes 13.4 billion years for its light to reach us.
What if there is advanced life in other galaxies? We may never find out
James Webb Space Telescope (JWST) He was busy observing the far ends of the universe, also known as the "Cosmic Dawn". This period, when the universe was only a few hundred million years old, is a treasure trove of information about how galaxies evolved when the universe was very young.
In October 2023 and January 2024, an international team of astronomers used Webb to observe galaxies as part of the JWST Advanced Deep Extragalactic Survey (JADES) programme. Using the Webb Near-Infrared Spectrometer (NIRSpec), the team obtained the spectrum of a record galaxy observed just 290 million years after the Big Bang.
In January 2024, NIRSpec observed this galaxy, JADES-GS-z14-0, for about ten hours, and when the spectrum was first processed, there was unambiguous evidence that the galaxy was indeed one redshift away from 14.32, breaking the record. For the previous outermost galaxy (z = 13.2 from JADES-GS-z13-0). Seeing this spectrum was very exciting for the entire team, given the mystery surrounding the source.
Explain Stefano Cargnani and Kevin Heinlein.
NIRCam data were used to select galaxies to be studied using spectroscopic observations. One of these galaxies, JADES-GS-z14-0 (shown in the image), was determined to be at a redshift of 14.32 (+0.08/-0.20), making it the current record holder for most distant known galaxies. This corresponds to a period of less than 300 million years after the Big Bang. In the background image, blue represents light at 0.9, 1.15 and 1.5 microns (filters F090W + F115W + F150W), green at 2.0 and 2.77 microns (F200W + F277W) and red at 3.56, 4.1 and 4.44 microns (F356W). + F410M + F444W). ). The plucking image shows light at 0.9 and 1.15 microns (F090W + F115W) in blue, 1.5 and 2.0 microns (F150W + F200W) in green, and 2.77 microns (F277W) in red.
Galaxy JADES-GS-z14-0 is an ancient galaxy
In addition to the impressive distance record, the The team also determined that the JADES-GS-z14-0 galaxy must be exceptionally bright. The source is more than 1,600 light-years across, “proving that the light we see comes mainly from young stars and not from nearby emissions from an accreting supermassive black hole.”
In order for there to be that much starlight, the mass of the galaxy would have to be hundreds of millions of times greater than the mass of the Sun, which leads to one of the most important questions that astronomers using Webb are trying to answer: “How could nature form such a bright, massive and large galaxy in less than 300 million years?"
While solving this mystery requires more science, the data offer even more surprising insights. The distant ancient galaxy is also not as blue as it should be, providing evidence that some of its light was turned red by dust, even at this very early stage of the universe.
Scientists used the NIRSpec (near infrared spectrometer) on NASA's James Webb Space Telescope to obtain a spectrum of the distant galaxy JADES-GS-z14-0 in order to precisely measure its redshift, and thus determine your age. The redshift can be determined from the location of the critical wavelength known as the Lyman-alpha fraction. The history of this galaxy dates back to less than 300 million years after the Big Bang.
Jake Hilton of the Steward Observatory and the University of Arizona used the Mid-Infrared Infrared (MIRI) Web Instrument to identify JADES-GS-z14-0 at longer wavelengths, “a remarkable achievement considering its distance.” MIRI's observation data includes wavelengths of light within the visible spectrum, although these wavelengths are red-shifted, outside Webb's detection capabilities.
Hilton's analysis of the object's brightness, along with extrapolations from other Webb observations, show evidence of an emission of strongly ionized gas in the galaxy, which appears as emission lines of hydrogen and oxygen.
This is another impressive aspect of this discovery, because it indicates that multiple generations of giant stars have already been born and died between the Big Bang and the JADES-GS-z14-0 observations. In other words, sometime between ground zero (the Big Bang) and 290 million years after the Big Bang, stars had already come and gone in the region around JADES-GS-z14-0.
All these observations, taken together, tell us that JADES-GS-z14-0 does not resemble the types of galaxies that theoretical models and computer simulations predict would exist in the early universe. Given the observed luminosity of the source, we can predict how it will grow over cosmic time, and so far we have found no suitable counterpart among the hundreds of other galaxies we observed at high redshift in our study.
Given the relatively small region of sky we surveyed to find JADES-GS-z14-0, its discovery has profound implications for the expected number of bright galaxies we see in the early universe, as discussed in another concurrent JADES study (Robertson et al.), Recently accepted). Astronomers are likely to find many more of these luminous galaxies, perhaps dating back even further, in the next decade with Webb. We're excited to see the extraordinary diversity of galaxies that existed in Cosmic Dawn!
The researchers explain.
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