This handout image obtained on May 30, 2024 courtesy of NASA/ESA/CSA STScI shows an infrared image from NASA’s James Webb Space Telescope. A galaxy, JADES-GS-z14-0 (shown in the pullout), was determined to be at a redshift of 14.32 (+0.08/-0.20), making it the current record-holder for the earliest known galaxy.
| Photo Credit: AFP

NASA’s James Webb Space Telescope has spotted the earliest-known galaxy, one that is surprisingly bright and big considering it formed during the universe’s infancy— at only 2% its current age.

Webb, which by peering across vast cosmic distances is looking way back in time, observed the galaxy as it existed about 290 million years after the Big Bang event that initiated the universe roughly 13.8 billion years ago, the researchers said. This period spanning the universe’s first few hundred million years is called cosmic dawn.

The telescope, also called JWST, has revolutionized the understanding of the early universe since becoming operational in 2022. The new discovery was made by the JWST Advanced Deep Extragalactic Survey (JADES) research team.

This galaxy, called JADES-GS-z14-0, measures about 1,700-light years across. A light year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). It has a mass equivalent to 500 million stars the size of our sun and was rapidly forming new stars, about 20 every year.

Before Webb’s observations, scientists did not know galaxies could exist so early, and certainly not luminous ones like this.

“The early universe has surprise after surprise for us,” said astrophysicist Kevin Hainline of Steward Observatory at the University of Arizona, one of the leaders of the study published online this week ahead of formal peer review.

“I think everyone’s jaws dropped,” added astrophysicist and study co-author Francesco D’Eugenio of the Kavli Institute for Cosmology at the University of Cambridge. “Webb is showing that galaxies in the early universe were much more luminous than we had anticipated.”

Until now, the earliest-known galaxy dated to about 320 million years after the Big Bang, as announced by the JADES team last year.

“It makes sense to call the galaxy big, because it’s significantly larger than other galaxies that the JADES team has measured at these distances, and it’s going to be challenging to understand just how something this large could form in only a few hundred million years,” Mr. Hainline said.

“The fact that it’s so bright is also fascinating, given that galaxies tend to grow larger as the universe evolves, implying that it would potentially get significantly brighter in the next many hundred million years,” Mr. Hainline said.

While it is quite big for such an early galaxy, it is dwarfed by some present-day galaxies. Our Milky Way is about 100,000 light years across, with the mass equivalent to about 10 billion sun-sized star.

The JADES team in the same study disclosed the discovery of the second oldest-known galaxy, from about 303 million years post-Big Bang. That one, JADES-GS-z14-1, is smaller – with a mass equal to about 100 million sun-sized stars, measuring roughly 1,000 light years across and forming about two new stars per year.

“These galaxies formed in an environment that was much more dense and gas-rich than today. In addition, the chemical composition of the gas was very different, much closer to the pristine composition inherited from the Big Bang – hydrogen, helium and traces of lithium,” Mr. D’Eugenio said.

Star formation in the early universe was much more violent than today, with massive hot stars forming and dying quickly, and releasing tremendous amount of energy through ultraviolet light, stellar winds and supernova explosions, Mr. D’Eugenio said.

Three main hypotheses have been advanced to explain the luminosity of early galaxies. The first attributed it to supermassive black holes in these galaxies gobbling up material. That appears to have been ruled out by the new findings because the light observed is spread over an area wider than would be expected from black hole gluttony.

It remains to be seen whether the other hypotheses – that these galaxies are populated by more stars than expected or by stars that are brighter than those around today – will hold up, Mr. D’Eugenio said.

The Event Horizon Telescope (EHT) collaboration, who produced the first ever image of our Milky Way black hole released in 2022, has captured a new view of the massive object at the centre of our Galaxy: how it looks in polarised light. This is the first time astronomers have been able to measure polarisation, a signature of magnetic fields, this close to the edge of Sagittarius A*. This image shows the polarised view of the Milky Way black hole. The lines overlaid on this image mark the orientation of polarisation, which is related to the magnetic field around the shadow of the black hole.
| Photo Credit: Reuters

Astronomers on Wednesday announced that they have detected a strong and organised magnetic field twisted in a spiral pattern around the Milky Way’s supermassive black hole, revealing previously unknown qualities of the immensely powerful object lurking at the center of our galaxy.

The structure of the magnetic field emanating from the edge of the black hole called Sagittarius A*, or Sgr A*, closely resembles one surrounding the only other black hole ever imaged, a larger one residing at the center of a nearby galaxy called Messier 87, or M87, the researchers said. This indicates that strong magnetic fields may be a feature common to black holes, they added.

The magnetic field around the M87 black hole, called M87*, enables it to launch powerful jets of material into space, the researchers said. This indicates that while such jets have not been detected to date around Sgr A*, they might exist – and might be observable in the near future, they added.

The researchers released a new image showing the environment around Sgr A* in polarised light for the first time, revealing the magnetic field structure. The polarised light comes from subatomic particles called electrons gyrating around magnetic field lines.

Sgr A* possesses 4 million times the mass of our sun and is located about 26,000 light-years – the distance light travels in a year, 5.9 trillion miles (9.5 trillion km) – from Earth.

“For a while, we’ve believed that magnetic fields play a key role in how black holes feed and eject matter in powerful jets,” said astronomer Sara Issaoun of the Center for Astrophysics – Harvard & Smithsonian and co-leader of the research.

“This new image, along with a strikingly similar polarisation structure seen in the much larger and more powerful M87* black hole, shows that strong and ordered magnetic fields are critical to how black holes interact with the gas and matter around them,” Issaoun added.

Black holes are extraordinarily dense objects with gravity so strong that not even light can escape, making viewing them extremely challenging.

“The magnetic field appears to be organised into a spiral, similar to M87*. This magnetic field geometry implies that the black hole can power very efficient jets that shoot off into the galaxy,” said another of the researchers, Center for Astrophysics astronomer Angelo Ricarte.

The new image, like the previous images of Sgr A* and the M87 black hole, was obtained using the Event Horizon Telescope (EHT) international scientific collaboration’s global network of observatories working collectively to observe radio sources associated with black holes.

A black hole’s event horizon is the point of no return beyond which anything – stars, planets, gas, dust and all forms of electromagnetic radiation – gets dragged into oblivion.

“By imaging polarised light from hot glowing gas near black holes, we are directly inferring the structure and strength of the magnetic fields that thread the flow of gas and matter that the black hole feeds on and ejects,” Issaoun said.

“Compared to the previous results, polaried light teaches us a lot more about the astrophysics, the properties of the gas, and mechanisms that take place as a black hole feeds,” Issaoun added.

Light is an oscillating electromagnetic wave that lets objects be seen. Light sometimes oscillates in a specific orientation, and that is called polarised light.

The M87 black hole has a mass 6 billion times that of our sun and inhabits the center of a giant elliptical galaxy. It ejects a powerful jet of plasma – gas so hot that some or all its atoms are split into the subatomic particles electrons and ions – visible at all wavelengths.

The evidence for a jet flowing from Sgr A* is mounting, the researchers said.

“One thing we’re really excited about is the prediction for a powerful jet. As our instrumentation improves in the upcoming years, if it exists, we should be able to tease it out of the data,” Ricarte said.

The findings were published in the Astrophysical Journal Letters.