Space

Cassiopeia A (Cas A) is a supernova remnant located about 11 000 light-years from Earth in the constellation Cassiopeia. It spans approximately 10 light-years. This image, released in April 2023, uses data from Webb’s Mid-Infrared Instrument (MIRI) to reveal Cas A in a new light.

On the remnant’s exterior, particularly at the top and left, lie curtains of material, appearing orange and red, that are due to emission from warm dust. This marks where ejected material from the exploded star is ramming into surrounding circumstellar material.

Interior to this outer shell lie mottled filaments of bright pink studded with clumps and knots. This is material from the star itself, and likely shines due to a mix of various heavy elements and dust emission. The stellar material can also be seen as fainter wisps near the cavity’s interior.

A loop represented in green extends across the right side of the central cavity. Its shape and complexity are unexpected and challenging for scientists to understand.

[Image description: A roughly square image is rotated clockwise about 45 degrees. Within the image is a roughly circular nebula with a complex structure. On the circle’s exterior lie curtains of material glowing orange. Interior to this outer shell lies a ring of mottled filaments of bright pink studded with clumps and knots. At centre right, a greenish loop extends from the right side of the ring into the central cavity. Translucent wisps of blue, green, and red appear throughout the image.]

CREDIT

NASA, ESA, CSA, D. Milisavljevic (Purdue University), T. Temim (Princeton University), I. De Looze (UGent), J. DePasquale (STScI)

This image from the NASA/ESA/CSA James Webb Space Telescope features an H II region in the Large Magellanic Cloud (LMC), a satellite galaxy of our Milky Way. This nebula, known as N79, is a region of interstellar atomic hydrogen that is ionised, captured here by Webb’s Mid-InfraRed Instrument (MIRI).

N79 is a massive star-forming complex spanning roughly 1630 light-years in the generally unexplored southwest region of the LMC. N79 is typically regarded as a younger version of 30 Doradus (also known as the Tarantula Nebula), another of Webb’s recent targets. Research suggests that N79 has a star formation efficiency exceeding that of 30 Doradus by a factor of two over the past 500 000 years.

This particular image centres on one of the three giant molecular cloud complexes, dubbed N79 South (S1 for short). The distinct ‘starburst’ pattern surrounding this bright object is a series of diffraction spikes. All telescopes which use a mirror to collect light, as Webb does, have this form of artifact which arises from the design of the telescope. In Webb's case, the six largest starburst spikes appear because of the hexagonal symmetry of Webb's 18 primary mirror segments. Patterns like these are only noticeable around very bright, compact objects, where all the light comes from the same place. Most galaxies, even though they appear very small to our eyes, are darker and more spread out than a single star, and therefore do not show this pattern.

At the longer wavelengths of light captured by MIRI, Webb’s view of N79 showcases the region’s glowing gas and dust. This is because mid-infrared light is able to reveal what is happening deeper inside the clouds (while shorter wavelengths of light would be absorbed or scattered by dust grains in the nebula). Some still-embedded protostars also appear in this field.

Star-forming regions such as this are of interest to astronomers because their chemical composition is similar to that of the gigantic star-forming regions observed when the Universe was only a few billion years old and star formation was at its peak. Star-forming regions in our Milky Way galaxy are not producing stars at the same furious rate as N79, and have a different chemical composition. Webb is now providing astronomers the opportunity to compare and contrast observations of star formation in N79 with the telescope’s deep observations of distant galaxies in the early Universe.

These observations of N79 are part of a Webb programme that is studying the evolution of the circumstellar discs and envelopes of forming stars over a wide range in mass and at different evolutionary stages. Webb’s sensitivity will enable scientists to detect for the first time the planet-forming dust discs around stars of similar mass to that of our Sun at the distance of the LMC.

This image includes 7.7-micron light shown in blue, 10 microns in cyan, 15 microns in yellow, and 21 microns in red (770W, 1000W, 1500W, and 2100W filters, respectively).

[Image description: A bright young star within a colourful nebula. The star is identifiable as the brightest spot in the image, surrounded by six large spokes of light that cross the image. A number of other bright spots can also be seen in the clouds, which are shown in great detail as layers of colourful wisps.]

CREDIT

ESA/Webb, NASA & CSA, M. Meixner

https://www.esa.int/ESA_Multimedia/Images/2024/01/A_massive_cluster_is_born

A beautiful but skewed spiral galaxy dazzles in today’s NASA/ESA Hubble Space Telescope Picture of the Week. This galaxy, called Arp 184 or NGC 1961, sits about 190 million light-years away from Earth in the constellation Camelopardalis (The Giraffe).

The name Arp 184 comes from the Atlas of Peculiar Galaxies, which was compiled by astronomer Halton Arp in 1966. The 338 galaxies in the atlas are oddly shaped, tending to be neither entirely elliptical nor entirely spiral-shaped. Many of the galaxies are in the process of interacting with other galaxies, while others are dwarf galaxies without well-defined structures. Arp 184 earned its spot in the catalogue thanks to its single broad, star-speckled spiral arm that appears to stretch toward us. The galaxy’s far side sports a few wisps of gas and stars but lacks a similarly impressive spiral arm.

This Hubble image combines data from three Snapshot observing programmes, which are composed of short observations that can be slotted into time gaps between other proposals. One of the three programmes targeted Arp 184 for its peculiar appearance. This programme surveyed galaxies listed in the Atlas of Peculiar Galaxies as well as A Catalogue of Southern Peculiar Galaxies and Associations, a similar catalogue compiled by Halton Arp and Barry Madore.

The remaining two programmes were designed to check up on the aftermath of fleeting astronomical events like supernovae and tidal disruption events — when a star is ripped apart after wandering too close to a supermassive black hole. Since Arp 184 has hosted four known supernovae in the past three decades, it’s a rich target for a supernova hunt.

[Image Description: A spiral galaxy seen at a skewed angle. Its centre is a bright spot radiating light. A thick, stormy disc of material surrounds this, with swirling strands of dark dust and bright spots of star formation strewn through the disc. A large spiral arm extends from the disc towards the viewer. Some foreg

CREDIT

ESA/Hubble & NASA, J. Dalcanton, R. J. Foley

(UC Santa Cruz), C. Kilpatrick

https://www.esa.int/About_Us/Week_in_images/Week_in_images_28_April_-_02_May_2025

Comment: I do not know why the last sentence in their description ends with an incomplete sentence.

Telescopes, including Hubble, have monitored the Eta Carinae star system for more than two decades. It has been prone to violent outbursts, including an episode in the 1840s during which ejected material formed the bipolar bubbles seen here.

Now, using Hubble’s Wide Field Camera 3 to probe the nebula in ultraviolet light, astronomers have uncovered the glow of magnesium embedded in warm gas (shown in blue) in places they had not seen it before. The luminous magnesium resides in the space between the dusty bipolar bubbles and the outer shock-heated nitrogen-rich filaments (shown in red). The streaks visible in the blue region outside the lower-left lobe are a striking feature of the image. These streaks are created when the star’s light rays poke through the dust clumps scattered along the bubble’s surface. Wherever the ultraviolet light strikes the dense dust, it leaves a long, thin shadow that extends beyond the lobe into the surrounding gas.

Eta Carinae resides 7500 light-years away.

CREDIT

NASA, ESA, N. Smith (University of Arizona, >Tucson), and J. Morse (BoldlyGo Institute, New York); CC BY 4.0

https://www.esa.int/ESA_Multimedia/Search?SearchText=carina&amp%3Bresult_type=images

[Image Description: An area of deep space with thousands of galaxies in various shapes and sizes on a black background. Most are circles or ovals, with a few spirals. More distant galaxies are redder in colour and smaller, down to being mere dots, while closer galaxies are a bit larger and white or blueish. A few gold-coloured galaxies are bunched closely together in the centre. Bright stars surrounded by spikes lie in our galaxy.]

https://esawebb.org/images/potm2504a/

https://cosmos.astro.caltech.edu/page/cosmosweb

ESA’s state-of-the-art Biomass satellite has launched aboard a Vega-C rocket from Europe’s Spaceport in French Guiana. The rocket lifted off on 29 April 2025 at 11:15 CEST (06:15 local time).

In orbit, this latest Earth Explorer mission will provide vital insights into the health and dynamics of the world’s forests, revealing how they are changing over time and, critically, enhancing our understanding of their role in the global carbon cycle. It is the first satellite to carry a fully polarimetric P-band synthetic aperture radar for interferometric imaging. Thanks to the long wavelength of P-band, around 70 cm, the radar signal can slice through the whole forest layer to measure the ‘biomass’, meaning the woody trunks, branches and stems, which is where trees store most of their carbon.

Vega-C is the evolution of the Vega family of rockets and delivers increased performance, greater payload volume and improved competitiveness.

CREDIT

ESA - S.Corvaja

This animation shows how Solar Orbiter obtains its high-resolution full Sun views. While both the Extreme Ultraviolet Imager (EUI) and Polarimetric and Helioseismic Imager (PHI) instruments on the spacecraft are capable of imaging the entire Sun in a single shot, their high-resolution cameras only cover a small patch of the Sun at any one time.

To get a high-resolution view of the full solar disc, Solar Orbiter is first oriented to point to different regions across the Sun, usually in a 5 x 5 grid, with images taken at each pointing direction. These are then stitched together to create a much larger ‘mosaic’.

Shown here is how this was done on 9 March 2025. The animation shows the Sun as seen by EUI's Full Sun Imager. At each pointing direction, highlighted by the dark squares, the EUI instrument captured six images at high resolution and two wide-angle views. These 200 individual images were then combined to create the widest high-resolution image of the Sun yet. Combining multiple images at each pointing direction improves the brightness and sharpness of the final image.

The green-red grid overlaid on the Sun shows the solar latitude and longitude lines, with the blue (red) vertical line indicating the Sun's south (north) pole. The crossing point of the thick yellow lines is the midpoint of Earth's view. Meanwhile, Solar Orbiter was viewing the Sun from a south solar latitude of 11.4 degrees at around 77 million km from the Sun.

On the bottom left of the animation you can see the date and time (in UTC), the distance of the spacecraft to the centre of the Sun in astronomical units (1 AU = 150 million km), and the field of view of the EUI Full Sun Imager in solar radii (1 R☉ = 696 000 km).

Solar Orbiter is a space mission of international collaboration between ESA and NASA. The Extreme Ultraviolet Imager (EUI) instrument is led by the Royal Observatory of Belgium (ROB).

[Video description: On a black background, the Sun looks like a slowly rotating warm yellow sphere with a surface covered with glowing messy hair. Moving, bright yellow arcs extend from the Sun's surface, while other regions look dark. Overlaid on this image are red-green dashed lattitude-longitude lines and a set of solid yellow lines at 0° longitude and −7.2° latitude. A vertical blue line extends from the Sun's south pole, and a red line from the north pole. As time progresses, a dark square moves from the northwest of the Sun down to the southwest in five steps, then repeats this one step to the east until it has covered all of the Sun's disc in a 5 x 5 grid.]

CREDIT ESA & NASA/Solar Orbiter/EUI Team, D. Berghmans (ROB)

https://www.esa.int/ESA_Multimedia/Sets/Solar_Orbiter_s_full_Sun_views/(result_type)/images

CREDIT ESA & NASA/Solar Orbiter/EUI Team, E. Kraaikamp (ROB)

I had no idea of this project from NASA. I don't understand why the national media has not covered this. I only just found out about it by watching a recent video by Peter Santenello.

The search for life beyond Earth has led scientists to explore many suggestive mysteries, from plumes of methane on Mars to clouds of phosphine gas on Venus. But as far as we can tell, Earth’s inhabitants remain alone in the cosmos.

Now a team of researchers is offering what it contends is the strongest indication yet of extraterrestrial life, not in our solar system but on a massive planet, known as K2-18b, that orbits a star 120 light-years from Earth. A repeated analysis of the exoplanet’s atmosphere suggests an abundance of a molecule that on Earth has only one known source: living organisms such as marine algae.

“It is in no one’s interest to claim prematurely that we have detected life,” said Nikku Madhusudhan, an astronomer at the University of Cambridge and an author of the new study, at a news conference on Tuesday. Still, he said, the best explanation for his group’s observations is that K2-18b is covered with a warm ocean, brimming with life.

“This is a revolutionary moment,” Dr. Madhusudhan said. “It’s the first time humanity has seen potential biosignatures on a habitable planet.”

The study was published Wednesday in the Astrophysical Journal Letters. Other researchers called it an exciting, thought-provoking first step to making sense of what’s on K2-18b. But they were reluctant to draw grand conclusions.

“It’s not nothing,” said Stephen Schmidt, a planetary scientist at Johns Hopkins University. “It’s a hint. But we cannot conclude it’s habitable yet.”

If there is extraterrestrial life on K2-18b, or anywhere else, its discovery will arrive at a frustratingly slow pace. “Unless we see E.T. waving at us, it’s not going to be a smoking gun,” said Christopher Glein, a planetary scientist at the Southwest Research Institute in San Antonio.

Canadian astronomers discovered K2-18b in 2017, while looking through ground-based telescopes in Chile. It was a type of planet commonly found outside our solar system, but one without any analog near Earth that scientists could study closely for clues.

These planets, known as sub-Neptunes, are much bigger than the rocky planets in our inner solar system, but smaller than Neptune and other gas-dominated planets of the outer solar system.

In 2021, Dr. Madhusudhan and his colleagues proposed that sub-Neptunes were covered with warm oceans of water and wrapped in atmospheres containing hydrogen, methane and other carbon compounds. To describe these strange planets, they coined a new term, “Hycean,” from a combination of the words “hydrogen” and “ocean.”

The launch of the James Webb Space Telescope in December 2021 allowed astronomers a closer look at sub-Neptunes and other distant planets.

As an exoplanet passes in front its host star, its atmosphere, if it has one, is illuminated. Its gases change the color of the starlight that reaches the Webb telescope. By analyzing these changing wavelengths, scientists can infer the chemical composition of the atmosphere.

While inspecting K2-18b, Dr. Madhusudhan and his colleagues discovered it had many of the molecules they had predicted a Hycean planet would possess. In 2023, they reported they had also detected faint hints of another molecule, and one of huge potential importance: dimethyl sulfide, which is made of sulfur, carbon, and hydrogen.

On Earth, the only known source of dimethyl sulfide is life. In the ocean, for instance, certain forms of algae produce the compound, which wafts into the air and adds to the sea’s distinctive odor. Long before the Webb telescope was launched, astrobiologists had wondered whether dimethyl sulfide might serve as a sign of life on other planets.

Last year, Dr. Madhusudhan and his colleagues got a second chance to look for dimethyl sulfide. As K2-18b orbited in front of its star, they used a different instrument on the Webb telescope to analyze the starlight passing through the planet’s atmosphere. This time they saw an even stronger signal of dimethyl sulfide, along with a similar molecule called dimethyl disulfide.

“It is a shock to the system,” Dr. Madhusudhan said. “We spent an enormous amount of time just trying to get rid of the signal.”

No matter how the scientists revisited their readings, the signal stayed strong. They concluded that K2-18b may in fact harbor a tremendous supply of dimethyl sulfide in its atmosphere, thousands of times higher than the level found on Earth. This would suggest that its Hycean seas are brimming with life.

Other researchers emphasized that much research remained to be done. One question yet to be resolved is whether K2-18b is in fact a habitable, Hycean world as Dr. Madhusudhan’s team claims.

In a paper posted online Sunday, Dr. Glein and his colleagues argued that K2-18b could instead be a massive hunk of rock with a magma ocean and a thick, scorching hydrogen atmosphere — hardly conducive to life as we know it.

Scientists will also need to run laboratory experiments to make sense of the new study — to recreate the possible conditions on sub-Neptunes, for instance, to see whether dimethyl sulfide behaves there as it does on Earth.

“It’s important to remember that we’re just starting to understand the nature of these exotic worlds,” said Matthew Nixon, a planetary scientist at the University of Maryland who was not involved in the new study.

Researchers want to wait to see what the Webb telescope finds as it continues to examine K2-18b; provocative early findings sometimes fade in the light of additional data. NASA has been designing and building more powerful space telescopes that will look specifically for signs of habitability on planets orbiting other stars, including K2-18b. Even if it takes years to decipher what’s happening on K2-18b, it could be worth it, scientists said.

“I’m not screaming, ‘aliens!’” said Nikole Lewis, an exoplanetary scientist at Cornell University. “But I always reserve my right to scream ‘aliens!’”

But Joshua Krissansen-Totton, an astrobiologist at the University of Washington, said he worried that American astrobiologists may not be able to follow up on the latest results on K2-18b.

The Trump administration is reportedly planning to cut NASA’s science budget in half, eliminating future space telescope and other astrobiology projects. If that happens, Dr. Krissansen-Totton said, “the search for life elsewhere would basically stop.” A correction was made on April 17, 2025 :

An earlier version of this article misstated the name of a scientific journal. It is Astrophysics Journal Letters, not Astrophysics Journal. The article also misstated the year and manner in which the planet K2-18b was discovered; it was 2015 using data from the Kepler Space Telescope, not 2017 using ground-based telescopes in Chile.

[Image description: What looks like a single large, bright star (but is two) shines with bright purple diffraction spikes at the center of a large, diffuse cylinder of gas and dust that is tipped to the right. At the center is a bright pink clumpy cloud that takes up about 25% of the view. There are two large rings seen at a roughly 60-degree angle that appear joined at top left and bottom right. The edges are denser, and form shallow V-shapes that go inward. The rings appear orange at top left and bottom right, and are blue at bottom and center right. There is diffuse orange material around the body. The black background of space is speckled with tiny stars and galaxies mostly in blues and yellows. Areas Webb did not observe are along the top edges, a thin vertical near the nebula at top left, and at the bottom left and right corners.]

https://esawebb.org/images/weic2508a/

The NASA/ESA/CSA James Webb Space Telescope has observed the well-known Ring Nebula with unprecedented detail. Formed by a star throwing off its outer layers as it runs out of fuel, the Ring Nebula is an archetypal planetary nebula. Also known as M57 and NGC 6720, it is both relatively close to Earth at roughly 2,500 light-years away.

This new image provides unprecedented spatial resolution and spectral sensitivity. In particular, Webb’s MIRI (Mid-InfraRed Instrument) reveals particular details in the concentric features in the outer regions of the nebulae’s ring (right).

There are some 20,000 dense globules in the nebula, which are rich in molecular hydrogen. In contrast, the inner region shows very hot gas. The main shell contains a thin ring of enhanced emission from carbon-based molecules known as polycyclic aromatic hydrocarbons (PAHs). Roughly ten concentric arcs located just beyond the outer edge of the main ring. The arcs are thought to originate from the interaction of the central star with a low-mass companion orbiting at a distance comparable to that between the Earth and the dwarf planet Pluto. In this way, nebulae like the Ring Nebula reveal a kind of astronomical archaeology, as astronomers study the nebula to learn about the star that created it.

The nebula is shaped like a distorted doughnut. We are gazing almost directly down one of the poles of this structure, with a brightly coloured barrel of material stretching away from us. Although the centre of this doughnut may look empty, it is actually full of lower density material that stretches both towards and away from us, creating a shape similar to a rugby ball slotted into the doughnut’s central gap.

The colourful main ring is composed of gas thrown off by a dying star at the centre of the nebula. This star is on its way to becoming a white dwarf – a very small, dense, and hot body that is the final evolutionary stage for a star like the Sun.

The Ring Nebula is one of the most notable objects in our skies. It was discovered in 1779 by astronomers Antoine Darquier de Pellepoix and Charles Messier, and was added to the Messier Catalogue. Both astronomers stumbled upon the nebula when trying to follow the path of a comet through the constellation of Lyra, passing very close to the Ring Nebula.

These observations were completed as part of the James Webb Space Telescope observing programme GO 1558. To learn more about the team’s research of these new observations, see the latest NASA Webb blog here.

The NASA/ESA Hubble Space Telescope released the observation of the Ring Nebula in 2013 and since then this has become one of the observatory’s most well-known images. From Earth’s perspective, the nebula looks roughly elliptical. However, astronomers combined ground-based data with observations by Hubble to explore the object’s structure, evolution, physical conditions and motion. This research revealed that the nebula is shaped like a distorted doughnut.

[Image description: This image of the Ring Nebula appears as a distorted doughnut. The nebula’s inner cavity hosts shades of red and orange, while the detailed ring transitions through shades of yellow in the inner regions and blue/purple in the outer region. The ring’s inner region has distinct filament elements.]

CREDIT

ESA/Webb, NASA, CSA, M. Barlow, N. Cox, R. Wesson

https://www.esa.int/Science_Exploration/Space_Science/Webb/Webb_captures_detailed_beauty_of_Ring_Nebula

A test rocket intended to kickstart satellite launches from Europe fell to the ground and exploded less than a minute after takeoff from Norway on Sunday, in what the German startup Isar Aerospace had described as an initial test.

The Spectrum started smoking from its sides and crashed back to Earth in a powerful explosion just after its launch from from the Andøya spaceport in the Arctic. Images were broadcast live on YouTube.

[Image Description: In the centre is an elliptical galaxy, seen as an oval-shaped glow around a small bright core. Around this is wrapped a broad band of light, appearing like a spiral galaxy stretched and warped into a ring, with bright blue lines drawn through it where the spiral arms have been stretched into circles. A few distant objects are visible around the ring on a black background.]

https://esawebb.org/images/potm2503a/

SMACSJ0028.2-7537 is the cluster that creates the lensing effect, the spiral galaxy is seen behind it.