Every Snowflake Needs a Speck of Dust and So Do Planets

A snowflake cannot form out of nothing. Water vapour will sit in the air quite happily, supercooled and reluctant, until it finds a speck of dust to build on and then it crystallises around it. Cosmochemists have had a version of that problem for decades. The early Solar System was a furnace of gas, and the first solid grains had to condense out of it somehow, yet condensing from a perfectly uniform gas is slow and difficult work. New research from Caltech, analysing fragments of a meteorite that fell over Mexico in 1969, suggests the seeds were already there. Buried inside the oldest solids we possess are specks of stardust from a star that lived and died before the Sun existed.

What If There's a Star Inside a Black Hole?

Ask what lies inside a black hole and the honest answer has always been a bit of a shrug and something about a singularity, a point where density becomes infinite and physics stops being able to tell you anything at all. It is the most unsatisfying answer in astrophysics, second only perhaps to what happened before the Big Bang. Now two theorists in China have produced a solution in which something else sits inside the horizon entirely, a neutron star, whole and intact, twelve kilometres across, its interior perfectly well behaved and apparently defying the laws of physics.

Watching the First Moments in a Star's Death

Astronomers were fortunate when the Einstein Probe detected the difficult-to-observe initial shock break out (SBO) from a supernova. The SBO is the first electromagnetic indication that a star is going to explode, and by observing it and the aftermath, researchers were able to determine what type of progenitor star exploded, and what it's pre-explosion environment was like.

The Odds of Finding Water on Mars

Mars has plenty of water, and almost all of it is in the wrong place. The poles are rich in ice, the equator, where you would actually want to land, has none within reach. That leaves the mid-latitudes, and until now the honest answer about what lies beneath them has been a bit of a shrug. Two new studies from the Planetary Science Institute have changed the shape of that answer. Rather than simply asking whether the data are consistent with buried ice, they have started calculating the odds and can now say, of a given patch of Martian ground, that there is a 64 per cent chance of finding ice if you dig there.

The Telescope That Points Itself

Time on a large professional telescope is one of the scarcest resources in science. Astronomers wait months for a few hours, and every one of those hours is a running argument with the weather, the Moon and the atmosphere. Point at the wrong target at the wrong moment and the data comes back soft, washed out, or useless, with the next chance half a year away. A team has now handed that argument to a machine. Their system was trained not on the rules astronomers use but on what astronomers actually did, night after night, for years.

Interstellar Travel III: Antimatter to the Rescue?

With the end of the Space Age and the winding down of the Cold War, scientists again returned to the question of interstellar flight. Having failed to realize a working concept that could be realized in the near term, more exotic ideas began to be considered, reflecting further breakthroughs in theoretical physics.

Ancient Maltese Seafarers Likely Navigated By The Stars

Ancient Maltese seafarers had both a complex cosmology and likely at least rudimentary skills in celestial navigation. It's thought that they used stars in the southern constellation of Crux to make their way around the south-central Mediterranean.