NASA’s James Webb Space Telescope has captured highly detailed images showing the complex layers of interstellar dust and gas. These observations, collected through light echoes from a supernova explosion, “are allowing astronomers to map the true 3D structure of this interstellar dust and gas (known as the interstellar medium) for the first time,” stated NASA in a release.

The light echoes, originating from a star’s collapse over 350 years ago, have travelled across vast distances to illuminate surrounding gas and dust. The explosion caused intense X-rays and ultraviolet light, which reached interstellar material, causing it to glow in the infrared. These cosmic remnants are now visible in stunning detail due to Webb’s advanced infrared technology.

“We were pretty shocked to see this level of detail,” said Jacob Jencson, principal investigator from Caltech.

The images reveal layers of interstellar material, some resembling the structure of an “onion”. Josh Peek of the Space Telescope Science Institute in Baltimore, said, “We see layers like an onion. We think every dense, dusty region that we see, and most of the ones we don’t see, look like this on the inside. We just have never been able to look inside them before.”

The Webb images show dense sheets of gas and dust stretching across hundreds of astronomical units. These sheet-like structures were not previously observed, challenging previous understanding of the interstellar medium.

“We did not know that the interstellar medium had structures on that small of a scale, let alone that it was sheet-like,” Peek said.

In addition to the sheet-like structures, Webb’s images reveal intricate magnetic features, suggesting interstellar magnetic fields influence these formations. Some areas appear as magnetic “islands” within the more uniform fields that dominate the interstellar medium, stated NASA.

The light echoes were first detected by NASA’s retired Spitzer Space Telescope, but Webb’s high-resolution imaging has provided clearer views of these cosmic phenomena. The echoes result from a supernova explosion, where light interacts with clumps of gas and dust, heating and illuminating them in an expanding pattern.

Armin Rest from the Space Telescope Science Institute likened the 3D mapping of the interstellar material to “the astronomical equivalent of a medical CT scan.”

“We have three slices taken at three different times, which will allow us to study the true 3D structure. It will completely change the way we study the interstellar medium,” Rest said.

Webb’s future observations will include spectroscopic observations of the light echoes using its Mid-Infrared Instrument (MIRI). This will allow scientists to study changes in the composition of the dust before, during, and after it is illuminated by the light echoes.

The discovery of these intricate details is a major milestone in space exploration. NASA Administrator Bill Nelson reflected on the mission’s success, saying, “Every image, every discovery, shows a portrait not only of the majesty of the universe but the power of the NASA team and the promise of international partnerships.”

Melbourne:

(The Conversation) On this day three years ago, we witnessed the nail-biting launch of the James Webb Space Telescope (JWST), the largest and most powerful telescope humans have ever sent into space.

It took 30 years to build, but in three short years of operation, JWST has already revolutionised our view of the cosmos.

It’s explored our own Solar System, studied the atmospheres of distant planets in search of signs of life and probed the farthest depths to find the very first stars and galaxies formed in the universe.

Here’s what JWST has taught us about the early universe since its launch – and the new mysteries it has uncovered.

Eerie blue monsters JWST has pushed the boundary of how far we can look into the universe to find the first stars and galaxies. With Earth’s atmosphere out of the way, its location in space makes for perfect conditions to peer into the depths of the cosmos with infrared light.

The current record for the most distant galaxy confirmed by JWST dates back to a time when the universe was only about 300 million years old. Surprisingly, within this short time window, this galaxy managed to form about 400 million times the mass of our Sun.

This indicates star formation in the early universe was extremely efficient. And this galaxy is not the only one.

When galaxies grow, their stars explode, creating dust. The bigger the galaxy, the more dust it has. This dust makes galaxies appear red because it absorbs the blue light. But here’s the catch: JWST has shown these first galaxies to be shockingly bright, massive and very blue, with no sign of any dust. That’s a real puzzle.

There are many theories to explain the weird nature of these first galaxies. Do they have huge stars that just collapse due to gravity without undergoing massive supernova explosions? Or do they have such large explosions that all dust is pushed away far from the galaxy, exposing a blue, dust-free core? Perhaps the dust is destroyed due to the intense radiation from these early exotic stars – we just don’t know yet.

Unusual chemistry in early galaxies The early stars were the key building blocks of what eventually became life. The universe began with only hydrogen, helium and a small amount of lithium. All other elements, from the calcium in our bones to the oxygen in the air we breathe, were forged in the cores of these stars.

JWST has discovered that early galaxies also have unusual chemical features.

They contain a significant amount of nitrogen, far more than what we observe in our Sun, while most other metals are present in lower quantities. This suggests there were processes at play in the early universe we don’t yet fully understand.

JWST has shown our models of how stars drive the chemical evolution of galaxies are still incomplete, meaning we still don’t fully understand the conditions that led to our existence.

Small things that ended the cosmic dark arges Using massive clusters of galaxies as gigantic magnifying glasses, JWST’s sensitive cameras can also peer deep into the cosmos to find the faintest galaxies.

We pushed further to find the point at which galaxies become so faint, they stop forming stars altogether. This helps us understand the conditions under which galaxy formation comes to an end.

JWST is yet to find this limit. However, it has uncovered many faint galaxies, far more than anticipated, emitting over four times the energetic photons (light particles) we expected.

The discovery suggests these small galaxies may have played a crucial role in ending the cosmic “dark ages” not long after the Big Bang.

The mysterious case of the little red dots The very first images of JWST resulted in another dramatic, unexpected discovery. The early universe is inhabited by an abundance of “little red dots”: extremely compact red colour sources of unknown origin.

Initially, they were thought to be massive super-dense galaxies that shouldn’t be possible, but detailed observations in the past year have revealed a combination of deeply puzzling and contradictory properties.

Bright hydrogen gas is emitting light at enormous speeds, thousands of kilometres per second, characteristic of gas swirling around a supermassive black hole.

This phenomenon, called an active galactic nucleus, usually indicates a feeding frenzy where a supermassive black hole is gobbling up all the gas around it, growing rapidly.

But these are not your garden variety active galactic nuclei. For starters: they don’t emit any detectable X-rays, as is normally expected. Even more intriguingly, they seem to have the features of star populations.

Could these galaxies be both stars and active galactic nuclei at the same time? Or some evolutionary stage in between? Whatever they are, the little red dots are probably going to teach us something about the birth of both supermassive black holes and stars in galaxies.

The impossibly early galaxies As well as extremely lively early galaxies, JWST has also found extremely dead corpses: galaxies in the early universe that are relics of intense star formation at cosmic dawn.

These corpses had been found by Hubble and ground-based telescopes, but only JWST had the power to dissect their light to reveal how long they’ve been dead.

It has uncovered some extremely massive galaxies (as massive as our Milky Way today and more) that formed in the first 700 million years of cosmic history. Our current galaxy formation models can’t explain these objects – they are too big and formed too early.

Cosmologists are still debating whether the models can be bent to fit (for example, maybe early star formation was extremely efficient) or whether we have to reconsider the nature of dark matter and how it gives rise to early collapsing objects.

JWST will turn up many more of these objects in the next year and study the existing ones in greater detail. Either way, we will know soon.

What’s next for JWST? Just within its first steps, the telescope has revealed many shortcomings of our current models of the universe. While we are refining our models to account for the updates JWST has brought us, we are most excited about the unknown unknowns.

The mysterious red dots were hiding from our view. What else is lingering in the depths of cosmos? JWST will soon tell us. (The Conversation)

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

Paris:

A planet relatively close to Earth could be the first ever detected with a potentially life-sustaining liquid ocean outside our Solar System, according to scientists using the James Webb space telescope.

More than 5,000 planets have been discovered outside of the Solar System so far, but only a handful are in what is called the “Goldilocks zone” — neither too hot or too cold — that could host liquid water, a key ingredient for life.

The exoplanet LHS 1140 b is one of the few in this habitable zone, and has been thoroughly scrutinised since it was first discovered in 2017.

It sits 48 light years from Earth, which equates to more than 450 trillion kilometres (280 trillion miles) — relatively close in the vast distances of space.

The exoplanet had been thought to be a small gas giant called a “mini-Neptune” with an atmosphere too thick with hydrogen and helium to support alien life.

However, new observations from the Webb telescope have confirmed that the exoplanet is in fact a rocky “super-Earth”.

It is 1.7 times bigger than Earth, but has 5.6 times its mass, according to a study published late Wednesday in The Astrophysical Journal Letters.

‘Best bet’ for ocean world

The Webb telescope was able to analyse the planet’s atmosphere as it passed in front of its star.

There were no signs of hydrogen or helium, which ruled out that the planet was a mini-Neptune.

The density of the planet indicates that it “actually has large quantities of water,” study co-author Martin Turbet of France’s CNRS scientific research centre told AFP.

It could be a truly immense amount of water.

All the water in Earth’s oceans represent only 0.02 percent of its mass. But 10 to 20 percent of the exoplanet’s mass was estimated to be water.

Whether or not this water is in liquid or ice form depends on the planet’s atmosphere.

“We do not have direct evidence that it has an atmosphere, but several elements point in that direction,” Turbet said.

Lead study author Charles Cadieux, a PhD student at the University of Montreal, said that “of all currently known temperate exoplanets, LHS 1140 b could well be our best bet to one day indirectly confirm liquid water on the surface of an alien world”.

One positive is that the planet is gently warmed by its red dwarf star, which is one-fifth the size of the Sun.

The exoplanet’s surface temperature should be fairly similar to that on Earth and Mars, Turbet said.

The presence of gasses such as carbon dioxide will play a key role in determining whether the planet is covered in ice or water.

Bull’s-eye ocean

One possibility is that the surface is mostly ice, but there is a vast liquid ocean where the planet is most exposed to its star’s heat.

This ocean could measure about 4,000 kilometres in diameter, around half the surface area of the Atlantic Ocean, modelling suggested.

Or the liquid water could be hidden under a thick shell of ice, like on the moons Ganymede, Enceladus or Europa orbiting around Jupiter and Saturn.

Webb’s instrument spotted signs that suggest “the presence of nitrogen,” Cadieux said, adding that more research was needed to confirm the finding.

Nitrogen is found everywhere on Earth, and is thought to be another potentially ingredient for life.

The researchers are hoping to get a few more hours of the Webb’s telescope’s precious time to find out more about LHS 1140 b.

It will take at least a year to confirm whether the exoplanet has an atmosphere, and two or three more to detect the presence of carbon dioxide, the researchers estimated.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)