Latest news with #JSWT
Indian Express
26-04-2025
- Science
- Indian Express
What is a dead galaxy? Astronomers spot one that stopped forming stars 700M years after Big Bang
More than 13 billion years after the Big Bang, astronomers have found the most distant galaxy ever seen using the James Webb Space Telescope (JSWT), except that this one has already stopped forming stars. The JWST spotted light from this newly discovered 'dead galaxy' called RUBIES-UDS-QG-z7,(the Red Unknowns: Bright Infrared Extragalactic Survey). It is said to be the most distant and massive 'dead galaxy' to have been found till date. The discovery was made by an international team, led by astronomers from the University of Geneva (UNIGE) in Geneva, Switzerland. 'For a long time, scientists thought that only actively star-forming galaxies should be observed in the very early Universe. The James Webb space telescope now reveals that galaxies stopped forming stars earlier than expected,' according to a press release issued by the University on April 2, 2025. So, what is a dead galaxy? What leads to their formation? What is galaxy quenching? Why does the recent discovery matter? What is a dead galaxy? A galaxy that has stopped creating new stars is referred to as a 'dead galaxy'. This happens when a galaxy uses up its supply of gas, mainly hydrogen, which is essential for the birth of new stars. Without enough cold and dense gas, star formation becomes stagnant. Processes like stellar winds, supernovae, or black hole activity can also expel this gas. As a result, the galaxy slowly fades, filled with aging stars and no new ones to replace them. The oldest known 'dead' galaxy, JADES-GS-z7-01-QU, was spotted by the James Webb Space Telescope (JWST) in March last year. It stopped producing stars when the universe was just 700 million years old. How do galaxies grow and die? Galaxies grow by absorbing gas and converting it into new stars. A galaxy may be able to draw gas more effectively as its mass grows, which speeds up the formation of new stars as this growth is forever. Galaxies eventually go through a process known as 'quenching,' in which they stop forming stars and, in effect, stop growing. What is quenching? The biggest galaxies, which frequently have an elliptical shape, are particularly prone to quenching. Before star formation stops, these galaxies typically take a long period to form by building up large stellar populations. One of the most significant unsolved problems in astrophysics is what exactly causes galaxies to quench. 'Finding the first massive galaxies that stopped making stars in the early universe is important because it helps us learn how they were formed.' according to a research paper published by University of Geneva. 'Scientists found one such galaxy that made stars equal to 15 billion times the mass of the Sun, but stopped creating new stars,' it added. What next? At a distance of about 650 light-years, RUBIES-UDS-QG-z7's small physical size indicates a high stellar mass density that is equivalent to the maximum central densities found in quiescent galaxies at slightly lower redshifts (z ~2–5). It is possible that these galaxies will grow into the cores of the local universe's oldest and most massive elliptical galaxies. The Atacama Large Millimeter/submillimeter Array (ALMA), Earth's largest radio telescope project, which has 66 antennas situated in the Atacama Desert region of Northern Chile, may be able to assist the JWST in its research of RUBIES-UDS-QG-z7. 'The discovery of RUBIES-UDS-QG-z7 provides the first strong evidence that the centres of some nearby massive ellipticals may have already been in place since the first few hundred million years of the Universe,' the research paper read.
Yahoo
27-03-2025
- Science
- Yahoo
Auroras on ice giant revealed: Space photo of the day
When you buy through links on our articles, Future and its syndication partners may earn a commission. For the first time, the James Webb Space Telescope (JSWT) has revealed bright auroral activity on the planet Neptune. Capturing the auroral activity on the ice giant has been long in coming, even though similar areas of trapped solar energetic particles have been successfully imaged in the atmospheres of Jupiter, Saturn and Uranus. Previously, the existence of auroral activity on Neptune was only hinted at, as instruments on NASA's Voyager 2 probe, which flew by the planet in 1989, and the Hubble Space Telescope were unable to capture the glow.'Turns out, actually imaging the auroral activity on Neptune was only possible with Webb's near-infrared sensitivity,' said Henrik Melin of Northumbria University, whose research while at the University of Leicester has now been published in the journal Nature. 'It was so stunning to not just see the auroras, but the detail and clarity of the signature really shocked me.' In Webb's images of Neptune, the aurora appears as lighter blue or cyan areas set against the blue planet. The auroral glow occurs because of the same basic interaction of solar particles interacting with the planet's atmosphere, but instead of being confined to the north and south poles, Neptune's auroras are located at the planet's mid-latitudes — roughly where South America is located on Earth. The location of Neptune's auroral glow is the result the planet's magnetic field, which is tilted by 47 degrees from the planet's rotation axis. Auroral activity occurs where a planet's magnetic fields converge into its atmosphere, so Neptune's auroras are found far from its rotational poles. The detection of Neptune's auroras will help astronomers better understand how particles from the sun interact with its atmosphere, providing a new area of study about ice giant planets. The data from the Webb Space Telescope also enabled measurements of the temperature at the top of Neptune's atmosphere for the first time since Voyager 2's flyby. Those results may point to why Neptune's auroras have gone unseen until now. "I was astonished — Neptune's upper atmosphere has cooled by several hundreds of degrees,' Melin said in a Space Telescope Science Institute release. "In fact, the temperature in 2023 was just over half of that in 1989." You can read more about Neptune and aurora on Earth. You can also read what it would be like to see aurora on other planets and how infrared aurora was first detected on Uranus in 2023.
Yahoo
08-02-2025
- Science
- Yahoo
The odds of an asteroid hitting Earth in 2032 just went slightly up
The chances that a space rock could hit Earth in less than a decade just went up slightly, according to NASA scientists. The asteroid 2024 YR4, which is expected to pass Earth in 2032, was recently calculated to have a 1-out-of-43 chance of striking our planet. By contrast, last week 2024 YR4 had only a 1-out-of-83 chance of striking our planet. Before you panic, however, note that 2024 YR4 only measures at a three on the Torino Scale. This scale, established by astronomers to help them assess the dangers posed by various near Earth objects, rocks that rank at a three merit concern for astronomers but not the general public. The risk level for this particular space rock has been updated to account for new calculations, but there is still a 97.7% chance that 2024 YR4 misses Earth entirely. "At this point humanity should not be alarmed about this,' Via Macarena Garcia Marin, a James Webb Space Telescope (JSWT) Project Scientist at the Space Telescope Science Institute, told Salon. 'In such cases it is typical for the odds of an impact to be higher when these objects are discovered, and drop as we learn more about them. The important aspect is to collect more data to really understand the situation. For instance, JWST now has a director's discretionary time program to evaluate its size." Even if it does hit Earth, experts cautioned that it's unlikely to cause much damage on a large-scale. Asked if we should be alarmed, Ethan Siegel, a theoretical astrophysicist, told Salon 'Absolutely not.' "It's likely less energetic than even the modest Chelyabinsk impactor from earlier this century," Siegel said, observing that we still haven't adequately measured 2024 YR4's potential collision course, (hence why its chance of hitting us rose) so scientists must treat any potential unwanted trespassers with the utmost caution. This is a reference to the Chelyabinsk meteor that entered Earth's atmosphere over Russia's Chelyabinsk Oblast in 2013. That object was approximately 60 ft (18 m) in diameter, large enough that upon entry it briefly shone brighter than the Sun at a range of up to 60 mi (100 km) away. It injured over 1,600 people, mostly from broken glass. "Any object that's going to miss us is going to be deemed a 'potential threat' until we measure it well enough to know its trajectory more certainly, and the small size and short period of observations that we have for this object is why we say it has a ~2% chance of impacting us," Siegel said. "With better data, we'll know whether it's going to strike us or simply pass us by, completely harmlessly."In the improbable event that 2024 YR4 does seem poised to hit Earth, scientists have plenty of plans — some echoing blockbusters like 'Deep Impact' — for addressing that crisis. Indeed, in 2022 NASA successfully demonstrated a 'Deep Impact'-inspired vehicle known as the Double Asteroid Redirection Test (DART) could collide with a near-Earth object. "We might even have to consider the severe measures of sending up a nuclear weapon to the surface of this asteroid in order to deflect it further," astronomer writer Dr. David Whitehouse told Sky News. Other scientists have suggested possible deflection tactics like lasers, kinetic impactors and so-called 'gravity tractors.' 2024 YR4 is currently moving farther away from Earth, which means astronomers will need larger telescopes to continue monitoring it. Despite this difficulty, 2024 YR4 should remain easily visible until April, although it is not expected to return to Earth's vicinity again until 2028. They are hoping that in the meantime, its motions will alter their calculations in such a way that makes them deem it even less likely to collide with Earth. The rock will remain on NASA's risk list until at least 2028. 'Ongoing observations from ground-based telescopes involved with the International Asteroid Warning Network will continue while the asteroid is still visible through April, after which it will be too faint to observe until around June 2028,' NASA said in a statement. As navigation engineer at the Jet Propulsion Laboratory and Center for Near-Earth Object Studies Davide Farnocchia told CNN, 'The longer we track an asteroid, the more precise the prediction. As we collect additional data, the uncertainty in the position of 2024 YR4 in 2032 will decrease. Given that the impact probability is only 1%, it is 99% likely that the Earth will eventually fall outside the swath of possible positions and that the probability would fall to zero.'
