Trailblazing radio telescope spies elusive hydrogen signal
Hydrogen is both the simplest atom in nature and the most abundant. It is the fuel that allows stars to shine and, in doing so, makes life possible.
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Now astronomers working with a unique radio telescope
Now astronomers working with a unique radio telescope in British Columbia have achieved the most distant measurement to date that shows how hydrogen atoms are distributed in the deep universe.
The result supports an emerging picture of how
The result supports an emerging picture of how matter organized itself after the Big Bang and built the universe we know today.
“What we really are tracing are huge clusters
“What we really are tracing are huge clusters and families of galaxies and the filaments that make up the dense structure of space,” said Mark Halpern, a professor at the University of British Columbia who is a principal investigator with the team that conducted the work.
He said that as he and his colleagues
He said that as he and his colleagues work to better understand the signal, it may allow for something more ambitious: a direct measurement of the rate at which the universe is expanding. This would provide an independent way to gauge the influence of dark energy, an unknown phenomenon that is thought to be causing the expansion to speed up. The detection was made using the Canadian Hydrogen Intensity Mapping Experiment, or CHIME, based in Penticton, B.C.
It consists of a series of trough-like antennas
It consists of a series of trough-like antennas which passively gather radio waves from the heavens. As the Earth turns, the antennas sweep across the northern sky, gradually collecting data from a vast volume of space. The heart of the instrument is a sophisticated computer system that disentangles all the information coming from many directions and turns it into a coherent picture of the radio sky.
Since it was first switched on in 2017
Since it was first switched on in 2017, CHIME has routinely detected a wide range of radio sources such as pulsars (rapidly spinning stellar corpses scattered throughout our Milky Way galaxy) and fast radio bursts (brief but intense blasts of radio energy coming from sources inside galaxies far beyond our own).
But CHIME’s original purpose was to detect the
But CHIME’s original purpose was to detect the much quieter and diffuse radio emission produced by hydrogen atoms in the cold depths between galaxies. Nine years after its work began, the project appears to have realized this goal.
In a pair of studies published Monday in
In a pair of studies published Monday in the Astrophysical Journal, astronomers revealed their detection of a hydrogen signal at approximately 8 billion light years from Earth, much farther than any previous measurement. An analysis of the signal shows how the hydrogen is clumped in space, which turns out to be in general agreement with other methods of mapping out the large scale structure of matter in the universe. “This is the measurement CHIME was designed to do,” Dr. Halpern said.
Team members said the result was harder to
Team members said the result was harder to obtain than expected in part because the combined radio noise emitted by electrons careening around the Milky Way is up to ten thousand times stronger than the faint hydrogen signal in the background.
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Trailblazing radio telescope spies elusive hydrogen signal
Hydrogen is both the simplest atom in nature and the most abundant.
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Source: Globe and Mail