Astronomy

NASA's Perseverance Mars rover will soon arrive at its first stop during its arduous trek to the western edge of Jezero Crater.

The astronauts and Crew Dragon capsule that will fly SpaceX's Crew-9 mission to the ISS have made it to Florida's Space Coast for their planned Sept. 26 liftoff.

Interacting with animals seems to provide emotional support to young people with a serious illness, even when the contact is via letters and not face to face

Interacting with animals seems to provide emotional support to young people with a serious illness, even when the contact is via letters and not face to face

Astrophotographer Miguel Claro captured an incredibly detailed timelapse of solar activity, revealing a roiling sun sprouting several massive loops of plasma.

A preview of Marvel Comics' "Alien: Romulus #1," a prequel that will be released in October.

An octopus will work with several different species of fish to find and catch prey - and punch those that aren't helping

An octopus will work with several different species of fish to find and catch prey - and punch those that aren't helping

Astronomer Jo Dunkley is planning to use the Simons Observatory to snare evidence for inflation, the theory that the universe expanded at incredible speed after its birth

Astronomer Jo Dunkley is planning to use the Simons Observatory to snare evidence for inflation, the theory that the universe expanded at incredible speed after its birth

The sunspot AR3835 erupted on Sunday (Sept. 22) during Earth's equinox when even a glancing blow can cause a geomagnetic storm.

Life remains busy for the astronauts aboard China's Tiangong space station, with a range of drills, maintenance and experiments to carry out.

If there really are advanced alien civilizations out there, you’d think they’d be easy to find. A truly powerful alien race would stride like gods among the cosmos, creating star-sized or galaxy-sized feats of engineering. So rather than analyzing exoplanet spectra or listening for faint radio messages, why not look for the remnants of celestial builds, something too large and unusual to occur naturally?

The most common idea is that aliens might build something akin to a Dyson sphere. In their need for more powerful energy sources, an advanced civilization might harness the entire output of a star. They wrap a star within a sphere to capture every last photon of stellar energy. Such an object would have a strange infrared or radio spectrum. An alien glow that is faint and unique. So astronomers have searched for Dyson spheres in the Milky Way, and have found some interesting candidates.

One major search was known as Project Hephaistos, which used data from Gaia, 2MASS, and WISE to look at five million candidate objects. From this they found seven unusual objects. They appear to be M-type red dwarfs at first glance, but have spectra that don’t resemble simple stars. This kind of star-like infrared object is exactly what you’d expect from a Dyson sphere. But of course extraordinary claims require extraordinary evidence, and that’s where things get fuzzy.

Almost immediately after the paper was published, other astronomers noted that the seven objects could also be hot Dust-Obscured Galaxies, or hotDOGs. These are quasars, so they appear star-like, but are obscured by such a tremendous amount of dust that they mostly emit in the infrared. And their spectra can be quite different from a M-type star. So the challenge is to distinguish between a hotDOG and a Dyson sphere. Which is where a new paper on the arXiv comes in.

Rather than trying to specifically distinguish between the two, the authors instead look at the distribution of known hotDOGS. They found that statistically about 1 in 3,000 quasars are of the hotDOG type, so that a broad search for Dyson spheres would likely include some dusty quasars. The authors go on to note that any civilization powerful enough to build star-scale structures would also have the ability to obscure their infrared signal. We can’t simply assume that aliens would build a Dyson sphere in such an obvious way. Overall, the authors argue, the seven candidate superstructures can be accounted for by hotDOGs and other phenomena, thus there is currently no clear evidence for alien superstructures.

Reference: Suazo, Matías, et al. “Project Hephaistos–II. Dyson sphere candidates from Gaia DR3, 2MASS, and WISE.” Monthly Notices of the Royal Astronomical Society 531.1 (2024): 695-707.

Reference: Blain, Andrew W. “Did WISE detect Dyson Spheres/Structures around Gaia-2MASS-selected stars?.” arXiv preprint arXiv:2409.11447 (2024).

The post Those Aren't Dyson Spheres, They're HotDOGs appeared first on Universe Today.

Ancient DNA extracted from layers of sediment in a Czech forest shows how a drop in biodiversity coincided with a shift to pig herding about 4000 years ago

Ancient DNA extracted from layers of sediment in a Czech forest shows how a drop in biodiversity coincided with a shift to pig herding about 4000 years ago

The Hubble tension, a longstanding problem in cosmology, could potentially be relieved if early dark energy is taken into account.

An atlas doesn’t seem to be an essential item in cars these days but think about them and most people will think about distances. An atlas of the stars not only covers distances but must also take into account time too. The Andromeda galaxy for example is so far away that its light takes 2.5 million years to reach us. A team of researchers have now built a catalogue that contains information on millions of galaxies including their distance and looks back in time up to 10 billion years!

Like anything that has – hmmmm lots of stuff, there are always catalogues to capture information about them. Astronomy is no different and there are plenty of catalogues; Messier, New General, Second Cambridge Catalogue of Radio Sources and the Two Micron All Sky Survey, the list goes on. Now a new catalogue has been created to provide information on millions of distant galaxies. It’s been created by a collaboration of organisations led by the Institute of Space Sciences as a result of the Physics of the Accelerating Universe Survey (PAUS.)

This new NASA/ESA Hubble Space Telescope shows Messier 96, a spiral galaxy just over 35 million light-years away in the constellation of Leo (The Lion). It is of about the same mass and size as the Milky Way. It was first discovered by astronomer Pierre Méchain in 1781, and added to Charles Messier’s famous catalogue of astronomical objects just four days later. The galaxy resembles a giant maelstrom of glowing gas, rippled with dark dust that swirls inwards towards the nucleus. Messier 96 is a very asymmetric galaxy; its dust and gas is unevenly spread throughout its weak spiral arms, and its core is not exactly at the galactic centre. Its arms are also asymmetrical, thought to have been influenced by the gravitational pull of other galaxies within the same group as Messier 96. This group, named the M96 Group, also includes the bright galaxies Messier 105 and Messier 95, as well as a number of smaller and fainter galaxies. It is the nearest group containing both bright spirals and a bright elliptical galaxy (Messier 105).

Over a period of 200 nights between 2015 and 2019, the teams embarked on their survey using the PAUCAM mounted upon the William Herschel Telescope (WHT) in La Palma. The camera is mounted at the prime focus of the WHT giving it a whopping 1 degree field of view. There are filter trays in front of the CCDs with 42 narrowband filters ranging from 4400 to 8600 angstroms. The team used the different filters to image the same field numerous times. The light from more distant objects will be shifted toward the red end of the spectrum and the multiple images of the same field will enable distance calculations to be made.

The William Herschel Telescope, part of the Isaac Newton group of telescopes, located on Canary Island. Credit: ing.iac.es

Overall, the survey covers 50 square degrees on the sky. To put that into context, the full moon measures half a degree across so the full survey maps out an area of sky equivalent to about 250 full moons. Having analysed the full set of images, the catalogue that has been developed includes data for 1.8 million objects which will be the foundations for astronomers to better understand the structure of the Universe. 

Understanding the structure of the universe is to understand the distribution of dark matter and dark energy. Dark energy is thought to make up 70 percent of the Universe but we still don’t know what it is. We can see its effect in the accelerated expansion of the Universe but its nature remains a mystery to us. The new survey will help to shine a light on dark energy with its comprehensive data set of galaxies that span more than 10 billion light years. 

This multiwavelength image of the Cloverleaf ORC (odd radio circle) combines visible light observations from the DESI (Dark Energy Spectroscopic Instrument) Legacy Survey in white and yellow, X-rays from XMM-Newton in blue, and radio from ASKAP (the Australian Square Kilometer Array Pathfinder) in red. X. Zhang and M. Kluge (MPE), B. Koribalski (CSIRO)

The results are a significant step forward in research into the cosmic distance scale and offers an extensive catalogue of photometric redshift measurements as they appeared billions of years ago. Over the months that follow, the team are planning on exploring galaxy clustering and galaxy shapes to help understand the evolution of the universe. 

Source : New cosmic distance catalogue to unlock the mysteries of Universe formation

The post A New Catalog Charts the Evolution of the Universe Over Time appeared first on Universe Today.

The largest Einstein Cross dwells among a rare arrangement of seven gravitationally lensed galaxies called the Carousel Lens located between 7 billion and 12 billion light-years from Earth.

Three crewmates have landed Earth after a record-long stay on the International Space Station (ISS) for two of them. For one, the 374 days has amounted to only a third of his total time in space.

Field trials indicate that pumping seawater onto the snow on top of Arctic sea ice can make the ice thicker, offering a possible way to preserve sea ice throughout the summer