Science Daily

In the years following the launch of NASA's Hubble Space Telescope, astronomers have tallied over 1 trillion galaxies in the universe. But only one galaxy stands out as the most important nearby stellar island to our Milky Way -- the magnificent Andromeda galaxy (Messier 31). It can be seen with the naked eye on a very clear autumn night as a faint cigar-shaped object roughly the apparent angular diameter of our Moon. A century ago, Edwin Hubble first established that this so-called 'spiral nebula' was actually very far outside our own Milky Way galaxy -- at a distance of approximately 2.5 million light-years or roughly 25 Milky Way diameters.

The Universe really seems to be expanding fast. Too fast, even. A new measurement confirms what previous -- and highly debated -- results had shown: The Universe is expanding faster than predicted by theoretical models, and faster than can be explained by our current understanding of physics. This discrepancy between model and data became known as the Hubble tension. Now, results provide even stronger support to the faster rate of expansion.

Leo P, a small galaxy and a distant neighbor of the Milky Way, is lighting the way for astronomers to better understand star formation and how a galaxy grows. Scientists have reported finding that Leo P 'reignited,' reactivating during a significant period on the timeline of the universe, producing stars when many other small galaxies didn't.

Galaxies like the Milky Way grow by merging with smaller galaxies over billions of years, unlike dwarf galaxies, which have long been thought to lack the heft to attract mass and grow in the same way. New observations challenge this view, suggesting that even dwarf galaxies can accrete mass from other small galaxies.

Pandora, a small satellite mission poised to provide in-depth study of at least 20 known planets orbiting distant stars to determine the composition of their atmospheres cleared an important milestone by completing the spacecraft bus, which acts as the spacecraft's 'brains.'

In 2018, a galaxy about 270 million light-years away from Earth exhibited a major increase in activity. It quieted down again by 2020 -- only to dramatically increase its output again in 2023. At that time, it began emitting radio waves at 60 times the previous intensity over just a few months, behavior which has never been monitored in real time for a supermassive black hole. Imaging also clearly shows a pair of oppositely directed plasma jets forming near the black hole and expanding outward over the course of 2023 -- 2024. The observation of jet formation in real time is another first. The data will help scientists understand how and under what conditions black holes produce jets.

For humans, the most important star in the universe is our Sun. The second-most important star is nestled inside the Andromeda galaxy. Don't go looking for it -- the flickering star is 2.2 million light-years away, and is 1/100,000th the brightness of the faintest star visible to the human eye. Yet, a century ago, its discovery by Edwin Hubble opened humanity's eyes as to how large the universe really is, and revealed that our Milky Way galaxy is just one of hundreds of billions of galaxies in the universe ushered in the coming-of-age for humans as a curious species that could scientifically ponder our own creation through the message of starlight.

Astronomers have detected an intensely brightening and dimming quasar that may help explain how some objects in the early universe grew at a highly accelerated rate. The discovery is the most distant object detected by the NuSTAR X-ray space telescope (which launched in 2012) and stands as one of the most highly 'variable' quasars ever identified.

New observational data and simulation models have confirmed a new type of planet unlike anything found in the Solar System. This provides another piece of the puzzle to understand how planets and planetary systems form.

Hot Jupiters are giant planets initially known to orbit alone close to their star. During their migration towards their star, these planets were thought to accrete or eject any other planets present. However, this paradigm has been overturned by recent observations, and the final blow could come from a new study demonstrating the existence of a planetary system, WASP-132, with an unexpected architecture. It not only contains a Hot Jupiter but also an inner Super-Earth and an icy giant planet.

By combining data from the DESI Legacy Imaging Surveys and the Gemini South telescope, astronomers have investigated three ultra-faint dwarf galaxies that reside in a region of space isolated from the environmental influence of larger objects. The galaxies, located in the direction of NGC 300, were found to contain only very old stars, supporting the theory that events in the early Universe cut star formation short in the smallest galaxies.

The night sky has always played a crucial role in navigation, from early ocean crossings to modern GPS. Besides stars, the United States Navy uses quasars as beacons. Quasars are distant galaxies with supermassive black holes, surrounded by brilliantly hot disks of swirling gas that can blast off jets of material. Following up on the groundbreaking 2020 discovery of newborn jets in a number of quasars, aspiring naval officer Olivia Achenbach of the United States Naval Academy has used NASA's Hubble Space Telescope to reveal surprising properties of one of them, quasar J0742+2704.

The name 'blue lurker' might sound like a villainous character from a superhero movie. But it is a rare class of star that NASA's Hubble Space Telescope explored by looking deeply into the open star cluster M67, roughly 2,800 light-years away.

Scientists have come a step closer to understanding how collisionless shock waves -- found throughout the universe -- are able to accelerate particles to extreme speeds.

Astronomers observed flashes of X-rays coming from a supermassive black hole at a steadily increasing clip. The source could be the core of a dead star that's teetering at the black hole's edge.

A researcher has used advanced models that indicate that the formation of Pluto and Charon may parallel that of the Earth-Moon system. Both systems include a moon that is a large fraction of the size of the main body, unlike other moons in the solar system. The scenario also could support Pluto's active geology and possible subsurface ocean, despite its location at the frozen edge of the solar system.

Taking advantage of a cosmic 'double lens,' astronomers resolved more than 40 individual stars in a galaxy so far away its light dates back to when the universe was only half its present age.

Physicists have proposed a solution to a long-standing puzzle surrounding the GD-1 stellar stream, one of the most well-studied streams within the galactic halo of the Milky Way.

Collaborative work by amateur and professional astronomers has helped to resolve a long-standing misunderstanding about the composition of Jupiter's clouds. Instead of being formed of ammonia ice -- the conventional view -- it now appears they are likely to be composed of ammonium hydrosulphide mixed with smog.

Hidden patterns in electric propulsion plasma beams could help ensure the success of long-term space missions.