NASA’s James Webb discovers one of the OLDEST galaxies in the universe – a system of stars that formed just 390 million years after the Big Bang
- Scientists said Maisie’s galaxy is one of the four earliest confirmed galaxies seen
- Has been named after daughter of astronomer who discovered it on her birthday
It was launched to peer back to the beginning of time and take pictures of the very first stars to shine in space.
Now, in the latest of its many exciting discoveries so far, the James Webb Space Telescope (JWST) has spotted one of the oldest galaxies in the universe.
Formed just 390 million years after the Big Bang, it has been named Maisie’s galaxy after the daughter of the astronomer who saw it for the first time on her birthday.
Scientists say it is one of the four earliest confirmed galaxies ever seen — although they are currently evaluating about 10 others that might be from an era even earlier than Maisie’s.
‘The exciting thing about Maisie’s galaxy is that it was one of the first distant galaxies identified by JWST, and of that set, it’s the first to actually be spectroscopically confirmed,’ said Steven Finkelstein, who headed up the research led by University of Texas at Austin.
Beginning of time: NASA’s James Webb Telescope has spotted one of the oldest galaxies in the universe. It has been named Maisie’s galaxy, after the daughter of the astronomer who discovered it
Instruments on the James Webb Space Telescope
NIRCam (Near InfraRed Camera) an infrared imager from the edge of the visible through the near infrared
NIRSpec (Near InfraRed Spectrograph) will also perform spectroscopy over the same wavelength range.
MIRI (Mid-InfraRed Instrument) will measure the mid-to-long-infrared wavelength range from 5 to 27 micrometers.
FGS/NIRISS (Fine Guidance Sensor and Near Infrared Imager and Slitless Spectrograph), is used to stabilise the line-of-sight of the observatory during science observations.
The way astronomers determine the age of a galaxy is complicated.
It involves working out when light left an object, which is calculated by measuring the galaxy’s redshift.
This is the amount that its colour has shifted because of its motion away from Earth.
Therefore, because we live in an expanding universe, the higher an object’s redshift, the older it is.
When it came to estimating the age of Maisie’s galaxy, Finkelstein and his team first based the redshift on photometry, which is the brightness of light in images using a small number of wide frequency filters.
This gave them a rough idea but to come up with a more accurate estimate they needed to apply for new measurements from JWST’s spectroscopic instrument, NIRSpec (Near InfraRed Spectrograph).
This splits an object’s light into many different narrow frequencies to more accurately identify its chemical makeup, heat output, intrinsic brightness and relative motion.
According to this latest spectroscopic analysis, Maisie’s galaxy is at a redshift of z=11.4.
The researchers also studied a galaxy called CEERS-93316, which was originally estimated to have formed just 250 million years after the Big Bang.
The researchers also studied a galaxy called CEERS-93316 (pictured), which was originally estimated to have formed just 250 million years after the Big Bang. However, it later emerged that scientists had been caught out by its blue tinge – and it actually formed one billion years after the universe was created
However, after carrying up the follow-up analysis it emerged that CEERS-93316 had a more modest redshift of z=4.9, which equates to about one billion years after the universe was created.
The reason the initial calculation was wrong was because scientists later discovered that hot gas in CEERS-93316 was emitting so much light in a few narrow frequency bands associated with oxygen and hydrogen that it made the galaxy appear much bluer than it really was.
This bluer tinge mimicked the signature that astronomers expected to see in very early galaxies.
However, it is actually a quirk of the photometric method which happens only for objects with redshifts of about 4.9.
‘This was a kind of weird case,’ Finkelstein said.
‘Of the many tens of high redshift candidates that have been observed spectroscopically, this is the only instance of the true redshift being much less than our initial guess.’
Not only was the galaxy unnaturally blue in its appearance, it was also found to be much brighter than current models predict for galaxies that formed so early in the universe.
‘It would have been really challenging to explain how the universe could create such a massive galaxy so soon,’ Finkelstein said.
‘So, I think this was probably always the most likely outcome, because it was so extreme, so bright, at such an apparent high redshift.’
JWST cost $10 billion (£7.4 billion) to build and was launched in December 2021 from Europe’s Spaceport near Kourou, French Guiana.
Its ultimate goal is to peer deeper back in time 13.5 billion years to a point within a mere 100-200 million years of the Big Bang.
The discovery of Maisie’s galaxy has been revealed in the journal Nature.
The James Webb Telescope: NASA’s $10 billion telescope is designed to detect light from the earliest stars and galaxies
The James Webb telescope has been described as a ‘time machine’ that could help unravel the secrets of our universe.
The telescope will be used to look back to the first galaxies born in the early universe more than 13.5 billion years ago, and observe the sources of stars, exoplanets, and even the moons and planets of our solar system.
The vast telescope, which has already cost more than $7 billion (£5 billion), is considered a successor to the orbiting Hubble Space Telescope
The James Webb Telescope and most of its instruments have an operating temperature of roughly 40 Kelvin – about minus 387 Fahrenheit (minus 233 Celsius).
It is the world’s biggest and most powerful orbital space telescope, capable of peering back 100-200 million years after the Big Bang.
The orbiting infrared observatory is designed to be about 100 times more powerful than its predecessor, the Hubble Space Telescope.
NASA likes to think of James Webb as a successor to Hubble rather than a replacement, as the two will work in tandem for a while.
The Hubble telescope was launched on April 24, 1990, via the space shuttle Discovery from Kennedy Space Centre in Florida.
It circles the Earth at a speed of about 17,000mph (27,300kph) in low Earth orbit at about 340 miles in altitude.
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