One of the last acts of NASA's Cassini spacecraft before its death plunge into Saturn's hydrogen and helium atmosphere was to coast between the planet and its rings and let them tug it around, essentially acting as a gravity probe. Precise measurements of Cassini's final trajectory have now allowed scientists to make the first accurate estimate of the amount of material in the planet's rings, weighing them based on the strength of their gravitational pull.

Today, astronomers have numerous extrasolar systems to study, but most look very different from our own. Determining how these solar systems — and ours — formed is challenging. New research presented at the 233rd Meeting of the American Astronomical Society in Seattle, Washington, on January 8 lends credence to an idea that goes against previous thoughts about planet formation, but has been gaining traction in the field...

Astronomers may have discovered a new way that stars can die. A mysteriously brief and bright burst whimsically called the “Cow” reveals an entirely new type of stellar death. The details of that stellar doom, however, remain hazy. Scientists are still debating whether the flare-up, spotted on June 16, 2018, was from an unusual type of star that was eaten by a black hole, or from an old, massive star exploding in a weird sort of supernova.

Models and observations indicate that both stars and planets form as a cloud of material collapses into a disk. If the process proceeds in an orderly manner, then the planets will all form from the same disk and thus orbit in the same plane. And—because material from the same disk will fall into the star, bringing its momentum with it—the star will rotate with its equator along the same plane. That should lead to a tidy system with the equator of the star lined up with the plane of any planets orbiting it.

One of the most cherished science fiction scenarios is using a black hole as a portal to another dimension or time or universe. That fantasy may be closer to reality than previously imagined. Black holes are perhaps the most mysterious objects in the universe. They are the consequence of gravity crushing a dying star without limit, leading to the formation of a true singularity – which happens when an entire star gets compressed down to a single point yielding an object with infinite density.

Using data from NASA's Kepler space telescope, citizen scientists have discovered a planet roughly twice the size of Earth located within its star's habitable zone, the range of orbital distances where liquid water may exist on the planet's surface. The new world, known as K2-288Bb, could be rocky or could be a gas-rich planet similar to Neptune. Its size is rare among exoplanets - planets beyond our solar system.

Late last year, astronomers announced that they’d found a super-Earth around Barnard’s star – one of the closest suns to our own. The discovery of a planet just six light-years away was enough to excite astronomers and the public alike. However, the researchers who found the planet said that they suspected the icy world couldn’t support life. But now, a group of astronomers are saying such pessimism may be premature. On Earth, geothermal vents produce heat and create unique environments where life thrives in places otherwise difficult to eke out a living – like the frigid, dark deep of the oceans.

Astronomers have discovered a planet twice the size of Earth, and it's within a zone that could allow liquid water to exist on its surface. The finding comes from data from NASA's Kepler space telescope, which ran out of fuel in October 2018. K2-288Bb, as the new planet is called, is located within its star's habitable zone, which is why liquid water is a possibility.

Hubble, the trusty space telescope that has been delivering gorgeous views of the cosmos for decades now, just delivered another gift. In a new composite image made up of many individual photos, Hubble shows us the nearby Triangulum galaxy in incredible detail. No, seriously, the final image is so huge that you’d never want to wait for it to load on a web page.

Back in the 1980s, astronomers were caught up in a debate so huge, you could drive a universe through it. The point of contention was a number called the Hubble constant, which describes the rate at which the cosmos is expanding and, by extension, how much time has passed since the Big Bang: the slower the expansion rate, the older the universe.

Astronomers have revealed details of mysterious signals emanating from a distant galaxy, picked up by a telescope in Canada. The precise nature and origin of the blasts of radio waves is unknown. Among the 13 fast radio bursts, known as FRBs, was a very unusual repeating signal, coming from the same source about 1.5 billion light years away.

It shines with a brightness equivalent to 600 trillion suns. “We don’t expect to find many quasars brighter than that in the whole observable universe,” said the astronomers. Researchers announced this week (January 9, 2019) at the 233rd meeting of the American Astronomical Society in Seattle, Washington, that they’ve discovered the brightest quasar yet known, detected from the period when the universe was just beginning to make luminous objects, such as stars and galaxies.

How did we get here? How do stars and planets come into being? What happens during a star's life, and what fate will its planets meet when it dies? Come along on this interstellar journey through time and scientific detective work.

Andromeda is the closest large galaxy to us. At 140,000 light years across, it’s 40% bigger than our 100,000 light year diameter Milky Way. Andromeda is 2.5 million light years away from us, or about 25 Milky Way diameters. Light takes 2.5 million years to pass between the two galaxies, so if a fancy Andromeda alien is viewing us with a telescope right now, it’s seeing a bunch of Australopithecus walking around being unappealing.

Tonight – January 2, 2019, according to clocks in the Americas – we reach Earth’s closest point to the sun for this entire year. That closest point comes at 11:20 p.m. CST (central U.S.) on January 2. It’ll be the morning of January 3 for Europe and Africa … later in the day January 3 for the rest of the world (January 3 at 05:20 UTC; translate to your time zone). Astronomers call this special point in our orbit perihelion, from the Greek roots peri meaning near and helios meaning sun.

Scientists studying the Tunguska impact of 1908 call for a special observing campaign next summer.

Astronomers attempting to capture the first images of the black hole at the heart of the Milky Way have given early hints that the ambitious project has been successful. The observations, by the Event Horizon Telescope, are expected to be unveiled in the spring in one of the most eagerly awaited scientific announcements of 2019. Now, a senior scientist on the project has said “spectacular” data was gathered during observations of two black holes, including Sagittarius A* at the centre of our own galaxy.

The speed and distance at which planets orbit their respective blazing stars can determine each planet's fate—whether the planet remains a longstanding part of its solar system or evaporates into the universe's dark graveyard more quickly.

Astronomers think they know how Uranus got flipped onto its side. According to Astronomers think they know how Uranus got flipped onto its side. According to detailed computer simulations, a body about twice the size of Earth slammed into Uranus between 3 to 4 billion years ago. The impact created an oddity in our Solar System: the only planet that rotates on its side. computer simulations, a body about twice the size of

The next generation exoplanet hunter is coming into its own. NASA’s Transiting Exoplanet Survey Satellite, or TESS, has already found eight confirmed planets in its first four months of observing — and some are unlike anything astronomers have seen before. “The torrent of data is starting to flow already,” TESS principal investigator George Ricker of MIT said January 7 in a news conference at a meeting of the American Astronomical Society.

Using detailed computer models of asteroidal-type objects between the Sun and Jupiter, two Harvard University researchers find that at least four known objects are likely to have origins from outside our solar system. After becoming gravitationally-trapped, the four potentially interstellar objects --- 2011 SP25, 2017 RR2, 2017 SV13, and 2018 TL6 --- are thought to spend most of their time between the orbits of Jupiter and Neptune. However, during their closest approaches to the Sun, they do pass through Earth’s neighborhood.

An international team of scientists have detected ripples in space and time, known as gravitational waves, from the biggest known black-hole collision that formed a new black hole about 80 times larger than the Sun – and from another three black-hole mergers. The Australian National University (ANU) is playing a lead role in Australia’s involvement with the gravitational wave discovery through a partnership in the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO), which is based in the United States.

An international team of researchers, including Jessica Spake and Dr David Sing from the University of Exeter, have detected the inert gas escaping from the atmosphere of the exoplanet HAT-P-11b – found 124 light years from Earth and in the Cygnus constellation.

The spectacular Geminid meteor shower peaks the night of December 13/14. Although many people consider it to be a poor cousin to August’s Perseid shower, the Geminids often put on a better show. This year, observers can expect to see up to 120 “shooting stars” per hour — an average of nearly two per minute — under a dark sky.

Astronomers observing the young protostar MM 1a have discovered an unusual method of binary star formation. While binary stars are not uncommon — they may account for half or more of all visible stars — the mechanics at work in the case of MM 1a are quite different than what we’d ordinarily expect.

As if battered post-Christmas finances, a looming disorderly Brexit and the prospect of a fresh nuclear arms race were not enough to dampen spirits, astronomers have declared that a nearby galaxy will slam into the Milky Way and could knock our solar system far into the cosmic void. The unfortunate discovery was made after scientists ran computer simulations on the movement of the Large Magellanic Cloud (LMC), one of the many satellite galaxies that orbits the Milky Way.

For the second time this year, the five brightest planets can be seen at the same time. You can catch them by looking towards the western sky after sunset. The planets will form a line rising up from the horizon. Mercury and Venus are low to the west, with bright Jupiter shining just above. Higher up in the northwestern sky is Saturn, and completing the set of five is the red planet Mars, high overhead.

New research shows a pattern of exoplanet sizes and spacing around other stars unlike what we see in our own system

As BepiColombo heads to Mercury — a long-neglected planet — Nature looks at which planets attract scientific missions, and why. Last week, the BepiColombo spacecraft successfully began its seven-year journey to Mercury — only the third-ever mission sent to the planet. The day before, scientists said that NASA’s next Mars rover — intended to be first to gather and return rock samples to Earth — should visit as many places on the red planet as possible.

Some of the winning images from the Royal Observatory Greenwich's annual competition.

The Gaia satellite has spotted an enormous 'ghost' galaxy lurking on the outskirts of the Milky Way. An international team of astronomers, including from the University of Cambridge, discovered the massive object when trawling through data from the European Space Agency's Gaia satellite. The object, named Antlia 2 (or Ant 2), has avoided detection until now thanks to its extremely low density as well as a perfectly-chosen hiding place, behind the shroud of the Milky Way's disc. The researchers have published their results online today.

About 8,000 light-years from Earth lies a star system unlike any astronomers have ever seen. And within that star system lies a ticking bomb - a gamma-ray burst.

A brisk stroll on Mars’ tiny, potato-shaped moon Phobos may just send you tumbling into space, finds a new report in Advances in Space Research. The new research (which admittedly seems a bit superfluous at first) looked at the latest published models of Phobos’ odd shape and dynamics to study how future exploration missions should navigate in orbit around, or on, the surface of the moon. The weird shape of the puny 14-mile-wide moon means that its gravitational field significantly varies along its surface.

A new value for the Hubble constant – the expansion rate of the universe — has been calculated by an international group of astrophysicists. The team used primordial distance scales to study more than 200 supernovae observed by telescopes in Chile and Australia. The new result agrees well with previous values of the constant obtained using a specific model of cosmic expansion, while disagreeing with more direct observations from the nearby universe – so exacerbating a long-running disagreement between cosmologists and astronomers.

Wherever humans go, our bacterial companions will follow. That’s as true in space as it is on Earth, and while we’ve known that microbial astronauts are present on the International Space Station, one group of researchers has just found a new reason to worry about them.