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The first image released from the James Webb Space Telescope in 2022 showing the ‘ SMACS0723 ’ galaxy cluster . Picture : Space Telescope Science Institute .
This will be a transformative survey because it ’ s such a large area .
‘ Unknown unknowns ’
Astronomers map the early universe
By Tim Dodd
Astronomers at Swinburne University will use the new James Webb Space Telescope , located 1.5 million km from earth , to make the first three-dimensional map of the universe as it was in the period known as “ cosmic morning ”, between 10 and 12 billion years ago .
Swinburne astronomer Karl Glazebrook leads a team which has won an extraordinarily valuable 615 hours of observing time on the telescope in the coming year .
Professor Glazebrook said the project , called JWST OutThere , would fill in missing knowledge about the formation and structure of galaxies in the early universe , born in the Big Bang about 14 billion years ago .
“ We will look at how the clustering structure of the universe grew ,” he said .
The $ 10bn James Webb telescope , built by NASA in partnership with the European and Canadian space agencies , was launched in late 2021 .
It has opened a window into the early universe beyond the dreams of astronomers only few decades ago .
James Webb is larger , and sees much further and more clearly , than the threedecade-old Hubble Space Telescope .
This also means it is seeing into the very early universe because , when a telescope picks up light from , say , 10 billion light years away , it is getting a picture of the universe as it was 10 billion years ago . The light has taken that long to get here . Professor Glazebrook leads a team of nearly 30 astronomers on the OutThere project , some of whom are at Swinburne and others who are in universities elsewhere in Australia and in Europe , the US and Canada .
He said the project would be looking into areas of space and time never observed before , looking out for both the “ known unknowns ” and the “ unknown unknowns ”.
One key set of data they know they will collect is the “ red shifts ” in the light spectra of galaxies which will show how fast they are receding as the universe expands , which also tells us how far away they are .
This will allow the team to build the first ever 3D map of galaxies in the cosmic morning .
“ Possible things we might discover are really bright galaxies in the early universe or weird quasars ,” Professor Glazebrook said . He said the observations might also make discoveries much nearer the earth , such as the much speculated about rogue planets – known as planemos , short for “ planetary mass objects ” – which are thought likely to be drifting in space after being torn loose from their home star . Professor Glazebrook ’ s OutThere team has been given the generous 615- hour allocation on the JWST because it piggybacks on other observations the telescope is making .
When the telescope is pointing at a particular target a separate team of astronomers is interested in , the OutThere team will use a wide-angle device to record , for an hour or two , an area of sky around the target about as wide as the full moon .
“ This will be a transformative survey because it ’ s such a large area ,” Professor Glazebrook said .
In total , he expects to get red shift data on about 60,000 galaxies from the cosmic morning period , 10-12 billion years ago .
“ We ’ re not going to get pretty pictures ,” he said . Instead , modern telescopes record digital data , only some of which make nice photos – “ but we ’ ll get fingerprints of every object ”.
Because there is such a flood of data , the hard part is to scrutinise and interpret it all . “ A big part of our research is to use AI methods to find what ’ s normal and what ’ s not normal ,” he said .
“ We also resort to the good old human eyeball and look at the spectra and say , ‘ Oh that ’ s funny ’.”
Observation time on the James Webb telescope is highly competitive and only about one out of seven applications by astronomers is accepted .
The telescope has to operate in a very cold environment , which is why it was launched so far from earth to a stable gravitational point known as L2 . ■
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