Space News & Blog Articles

Astronomers have been assessing a new machine learning algorithm to determine how reliable it is for finding gravitational lenses hidden in images from all sky surveys. This type of AI was used to find about 5,000 potential gravitational lenses, which needed to be confirmed. Using spectroscopy for confirmation, the international team has now determined the technique has a whopping 88% success rate, which means this new tool could be used to find thousands more of these magical quirks of physics.

“These lenses are very small so if you have fuzzy images, you’re not going to really be able to detect them,” said Dr. Kim-Vy Tran, from the ARC Centre of Excellence for All Sky Astrophysics in 3-Dimensions (ASTRO3D) and the University of NSW (UNSW), who led the study. “Our spectroscopy allowed us to map a 3D picture of the gravitational lenses to show they are genuine and not merely chance superposition.”

Scientists say that gravitational lenses could transform our ability to chart the evolution of galaxies since the Big Bang. This type of lensing occurs when light from a distant object is distorted by a closer massive object along the same line of sight. This distortion effectively creates a giant lens which magnifies the background light source, allowing astronomers to observe objects embedded within those lens-created arcs and rings that are otherwise be too far and too dim to see.

Gravitational lenses are a great tool for astronomy. Not only do gravitational lenses reveal distant objects like galaxies, but it can also provide information about how far away these galaxies are. Additionally, analyzing the nature of gravitational lensing patterns tells astronomers about the way dark matter is distributed within galaxies. It also provides a way to investigate both the development of structure in the universe and the expansion of the universe.

The machine learning algorithm was pioneered by Colin Jacobs at Swinburne University in Australia. He used the technique to sift through tens of millions of galaxy images to prune the sample down to 5,000. Other surveys, like dark energy surveys, have also been used to find lensing candidates.

Here’s a sharper view of Dimorphos, the small asteroid moonlet that the DART (Double Asteroid Redirection Test) spacecraft intentionally crashed into. Eydeet on Imgur created a higher resolution image of Dimorphos by stacking the last few images received from the spacecraft before impact.

First impressions? It’s an egg-shaped rubble pile.

What we know:

Dimorphos is about 160 meters (530 feet) in diameter and it orbits a larger, 2,560-foot (780-meter) asteroid called Didymos. This asteroid duo makes the perfect target for this demonstration test, as NASA says the impact should change the way Dimorphos orbits Didymos. DART crashed into the asteroid at roughly 22,530 km/hr (14,000 mph), which is expected to have slightly slowed the asteroid’s orbital speed. One NASA scientist explained, the impact was “like ramming a golf cart into the Great Pyramid.”

Scientists are now poring over the data to determine how much the orbit was changed. This will show if DART’s 570 kilograms (1,260-pounds) of impact is a viable mitigation technique for protecting the planet from an Earth-bound asteroid or comet, if one were discovered.

The orbit of Didymos and Dimorphos ranges from just outside the orbit of Earth (about 1 AU) to a bit beyond the orbit of Mars (about 2.27 AU. It takes 2.11 years for the pair to make a trip around the Sun.

When you imagine the collision of galaxies, you probably think of something violent and transformational. Spiral arms ripped apart, stars colliding, cats and dogs living together, mass hysteria. The reality is much less dramatic. As a recent study shows, our galaxy is in a collision right now.

Although the big collision between the Milky Way and the Andromeda Galaxy is still yet to come, our galaxy has undergone galactic collisions in the past. The most well-understood collision is that between the Milky Way and the Sagittarius Dwarf Galaxy. This small galaxy first impacted the Milky Way about 6 billion years ago and may have triggered the star-forming period that produced our Sun.

But collisions on a galactic scale are slow and tedious. Over billions of years, the core of the Sagittarius galaxy has struck the Milky Way a few times as it is gradually ripped apart. It can now be seen as arcs of stars encircling our galaxy. It stands to reason that such an ancient collision is long over, but this recent study shows it still has ripple effects on the Milky Way. Literally.

The team used data from the Gaia spacecraft and looked at the motion of stars near the outer edge of the Milky Way. The velocities of these stars showed a rippled distribution of motion, created by Sagittarius the way a dropped stone might trigger ripples on a pond. Overall the stars at the outer edge of the Milky Way are not in gravitational equilibrium, which is a fancy way of saying our galaxy is still feeling the effects of the collision.

The team was surprised by the level of detail the Gaia data provided. By measuring the positions of more than two billion stars, and the motions of more than 30 million, Gaia has given the team a kind of galactic seismology that can be used to trace the dynamic history and evolution of the Milky Way.

Astronomers studying a stellar cluster within the Small Magellanic Cloud (SMC) have found young stars spiraling in towards the center of the cluster. The cluster, NGC 346, is an open cluster embedded within a glowing cloud of gas, which is typical of stellar nurseries – places where new stars are formed. The outer spiral arm of this star forming region appears to be funneling gas, dust and new stars into the center, which researchers describe as an efficient way to fuel the birth of new stars.

The SMC is a small satellite galaxy of the Milky Way, visible with the naked eye to Southern hemisphere observers under dark skies. It is about 200 000 light years away, and contains a number of nebulae and clusters. One of these, NGC 346, combines a population of bright, new stars, and their still-collapsing stellar nursery of gas and dust, which continues to produce new stars.

The region is only 150 light years across, and has a mass of about 50 000 Suns. Its unusually high rate of star-formation, and its intriguing shape, have been an interesting puzzle to astronomers for some time. This latest image offers some fresh clues to help us understand what’s going on. It combines observations from the Hubble Space Telescope (HST) and the European Southern Observatory’s (ESO) Very Large Telescope (VLT).

Elena Sabbi of the Space Telescope Science Institute in Baltimore, and leader of the study, had this to say:

“Stars are the machines that sculpt the Universe. We would not have life without stars, and yet we don’t fully understand how they form. We have several models that make predictions, and some of these predictions are contradictory. We want to determine what is regulating the process of star formation, because these are the laws that we need to also understand what we see in the early Universe.”