A tiny red spot caught in the distant background of the James Webb Space Telescope’s first “deep-field” image could transform our understanding of the early universe, astronomers say.
The inconspicuous blob is an unnamed ancient galaxy that is 13.1 billion years old, only several hundred million years younger than the birth of the universe. Of all the galaxies captured in the image, it is the farthest from Earth.
It was captured in the deepest, sharpest infrared image of the distant universe ever recorded, and released to the world as part of the $10bn (£7.4m) observatory. First series of full color photos last week.
When researchers spread the light from an individual galaxy into a spectrum, they can learn about the chemical composition, temperature, and density of the galaxy’s ionized gas.
For example, the spectrum of this galaxy will reveal the properties of its gas, indicating how its stars are forming and how much dust it contains.
Such information has never before been detected from so far away with this quality.
Hidden secrets: A tiny red spot trapped in the distant background of the James Webb Space Telescope’s first ‘deep field’ image could help uncover the chemistry of the early universe
When researchers spread the light from an individual galaxy into a spectrum (pictured), they can learn about the chemical composition, temperature, and density of a galaxy’s ionized gas.
Far away: It was captured in the deepest, sharpest infrared image of the distant universe ever recorded (pictured) and released to the world last week as part of the first Webb images.
The spectrum itself was produced by Webb’s NIRSpec instrument, which uses tiny windows to isolate and analyze light from objects within the telescope’s field of view.
It meant that only light from stars in the old galaxy was allowed through, to reveal their chemical signatures, while other light from nearby bright objects was blocked.
Among the different elements within the galaxy was a fingerprint of glowing oxygen gas, which is known as an emission line.
NIRSpec team member Andrew Bunker, from the University of Oxford, said experts expected to see this line in distant galaxies, but expected to have to search for “dozens or hundreds” of targets before detecting it.
“I don’t think we really dreamed that at the first snap, essentially advertising, it would be there. That’s really quite incredible,’ he told the new scientist.
The reason the oxygen emission line is important is because astronomers use it to calibrate their measurements of the galaxy compositions.
If it can then be compared to other emission lines in a galaxy’s light, then it’s possible to figure out how many chemicals there are in the galaxy, based on chemical fingerprints in a spectrum.
This has been done before for nearby galaxies but not for distant galaxies like the red spot in Webb’s deep field.
As astronomers begin to analyze the Webb data, we will learn a great deal about the galaxies that existed throughout cosmic time, and how they compare to the beautiful spiral and elliptical galaxies in the nearby universe.
More spectra like this one will allow scientists to explore how the proportion of elements heavier than helium in distant galaxies has changed over time.
“It gives you data points on that evolution,” Emma Chapman, an astrophysicist at the University of Nottingham, told New Scientist.
The spectrum itself was produced by Webb’s NIRSpec instrument, which uses tiny windows to isolate and analyze light from objects within the telescope’s field of view.
Webb’s infrared capabilities allow him to ‘see back in time’ to the Big Bang, which occurred 13.8 billion years ago. Light waves move extremely fast, about 186,000 miles (300,000 km) per second, every second. The further away an object is, the further back in time we are looking. This is due to the time it takes for light to travel from the object to us.
‘Then you can start thinking about how quickly the first stars died and polluted the gas [to] create the second generation of stars that this galaxy is made of.
Last week, Webb’s dazzling and unprecedented images of a “stellar nursery”, a dying star covered in dust and a “cosmic dance” between a group of galaxies, were revealed to the world for the first time.
It ended months of waiting and feverish anticipation as people around the world received the first batch of a trove of images that will culminate in the first look at the dawn of the universe.
Webb’s infrared capabilities mean he can “see back in time” to within about 100-200 million years of the Big Bang, allowing him to take pictures of the first stars that shone in the universe more than 13.5 billion years ago. .
His first images of nebulae, an exoplanet and clusters of galaxies caused a great celebration in the scientific world, in what was hailed as a “great day for humanity”.
Researchers will soon begin to learn more about the masses, ages, histories, and compositions of galaxies, as Webb seeks to explore the oldest galaxies in the universe.
THE JAMES WEBB TELESCOPE
The James Webb Telescope has been described as a ‘time machine’ that could help unlock the secrets of our universe.
The telescope will be used to look at the first galaxies that were born in the early universe more than 13.5 billion years ago and look at the sources of stars, exoplanets and even the moons and planets of our solar system.
The large telescope, which has already cost more than $7bn (£5bn), is seen as a successor to the orbiting Hubble Space Telescope.
The James Webb Telescope and most of its instruments have an operating temperature of about 40 Kelvin, about minus 387 Fahrenheit (minus 233 Celsius).
It is the largest and most powerful orbiting space telescope in the world, capable of looking 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 be working together for a while.
The Hubble Telescope was launched on April 24, 1990 via the Space Shuttle Discovery from the Kennedy Space Center in Florida.
It circles the Earth at a speed of about 17,000 mph (27,300 kph) in low Earth orbit at about 340 miles in altitude.
