A bizarre form of water may exist all over the universe

Joshua Sokol writes:

Recently at the Laboratory for Laser Energetics in Brighton, New York, one of the world’s most powerful lasers blasted a droplet of water, creating a shock wave that raised the water’s pressure to millions of atmospheres and its temperature to thousands of degrees. X-rays that beamed through the droplet in the same fraction of a second offered humanity’s first glimpse of water under those extreme conditions.

The X-rays revealed that the water inside the shock wave didn’t become a superheated liquid or gas. Paradoxically — but just as physicists squinting at screens in an adjacent room had expected — the atoms froze solid, forming crystalline ice.

“You hear the shot,” said Marius Millot of Lawrence Livermore National Laboratory in California, and “right away you see that something interesting was happening.” Millot co-led the experiment with Federica Coppari, also of Lawrence Livermore.

The findings, published today in Nature, confirm the existence of “superionic ice,” a new phase of water with bizarre properties. Unlike the familiar ice found in your freezer or at the north pole, superionic ice is black and hot. A cube of it would weigh four times as much as a normal one. It was first theoretically predicted more than 30 years ago, and although it has never been seen until now, scientists think it might be among the most abundant forms of water in the universe. [Continue reading…]

A new glimpse of the evolving universe


HubbleSite reports:

Astronomers have put together the largest and most comprehensive “history book” of galaxies into one single image, using 16 years’ worth of observations from NASA’s Hubble Space Telescope.

The deep-sky mosaic, created from nearly 7,500 individual exposures, provides a wide portrait of the distant universe, containing 265,000 galaxies that stretch back through 13.3 billion years of time to just 500 million years after the big bang. The faintest and farthest galaxies are just one ten-billionth the brightness of what the human eye can see. The universe’s evolutionary history is also chronicled in this one sweeping view. The portrait shows how galaxies change over time, building themselves up to become the giant galaxies seen in the nearby universe. [Continue reading…]

Bjørn Ekeberg writes:

What do we really know about our universe?



In recent months, new measurements of the Hubble constant, the rate of universal expansion, suggested major differences between two independent methods of calculation. Discrepancies on the expansion rate have huge implications not simply for calculation but for the validity of cosmology’s current standard model at the extreme scales of the cosmos.

Another recent probe found galaxies inconsistent with the theory of dark matter, which posits this hypothetical substance to be everywhere. But according to the latest measurements, it is not, suggesting the theory needs to be reexamined. [Continue reading…]

Mystery of the universe’s expansion rate widens with new Hubble data

NASA reports:





These most precise Hubble measurements to date bolster the idea that new physics may be needed to explain the mismatch. [Continue reading…]

2014 comet may be first known interstellar visitor to have come close to Earth

Science News reports:


The first interstellar visitor known to have come close to Earth was the roughly 400-meter-wide asteroid named ‘Oumuamua.’ It swooped within about 24 million kilometers of the planet in October 2017. Its sharp-angled approach to the solar system and equally strange departure led astronomers to suggest that ‘Oumuamua could have been anything from a fluffy skeleton of a comet to an alien spaceship.

If there was one interstellar interloper, astronomers reasoned, there would likely have been more, including some that collided with Earth. [Continue reading…]

Regaining a sense of proportion in our universe


How scientists took the first picture of a black hole

Science News reports:

Black holes are extremely camera shy. Supermassive black holes, ensconced in the centers of galaxies, make themselves visible by spewing bright jets of charged particles or by flinging away or ripping up nearby stars. Up close, these behemoths are surrounded by glowing accretion disks of infalling material. But because a black hole’s extreme gravity prevents light from escaping, the dark hearts of these cosmic heavy hitters remain entirely invisible.

Luckily, there’s a way to “see” a black hole without peering into the abyss itself. Telescopes can look instead for the silhouette of a black hole’s event horizon — the perimeter inside which nothing can be seen or escape — against its accretion disk. That’s what the Event Horizon Telescope, or EHT, did in April 2017, collecting data that has now yielded the first image of a supermassive black hole, the one inside the galaxy M87.

“There is nothing better than having an image,” says Harvard University astrophysicist Avi Loeb. Though scientists have collected plenty of indirect evidence for black holes over the last half century, “seeing is believing.”

Creating that first-ever portrait of a black hole was tricky, though. Black holes take up a minuscule sliver of sky and, from Earth, appear very faint. The project of imaging M87’s black hole required observatories across the globe working in tandem as one virtual Earth-sized radio dish with sharper vision than any single observatory could achieve on its own.

Weighing in around 6.5 billion times the mass of our sun, the supermassive black hole inside M87 is no small fry. But viewed from 55 million light-years away on Earth, the black hole is only about 42 microarcseconds across on the sky. That’s smaller than an orange on the moon would appear to someone on Earth. Still, besides the black hole at the center of our own galaxy, Sagittarius A* or Sgr A* — the EHT’s other imaging target — M87’s black hole is the largest black hole silhouette on the sky.

Only a telescope with unprecedented resolution could pick out something so tiny. (For comparison, the Hubble Space Telescope can distinguish objects only about as small as 50,000 microarcseconds.) A telescope’s resolution depends on its diameter: The bigger the dish, the clearer the view — and getting a crisp image of a supermassive black hole would require a planet-sized radio dish. [Continue reading…]

Is methane in Mars’ atmosphere evidence of life?

The New York Times reports:


Why the methane is there is still a bewildering mystery. It may even point to present-day Martian microbes living in the rocks below the surface.

In Nature Geoscience on Monday, scientists working with the European Space Agency’s Mars Express orbiter reported that in the summer of 2013, the spacecraft detected methane within Gale Crater, a 96-mile-wide depression near the Martian equator.

That is noteworthy, because NASA’s Curiosity rover has been exploring that region since 2011, and in the summer of 2013 it, too, measured a marked rise of methane in the air that lasted at least two months.

“Our finding constitutes the first independent confirmation of a methane detection,” said Marco Giuranna, a scientist at the National Institute for Astrophysics in Italy, in an email. Dr. Giuranna is principal investigator for the Mars Express instrument that made the measurements.


Evidence of the most significant event in the history of life on Earth

Douglas Preston writes:



Some of the ejecta escaped Earth’s gravitational pull and went into irregular orbits around the sun. Over millions of years, bits of it found their way to other planets and moons in the solar system. Mars was eventually strewn with the debris—just as pieces of Mars, knocked aloft by ancient asteroid impacts, have been found on Earth. A 2013 study in the journal Astrobiology estimated that tens of thousands of pounds of impact rubble may have landed on Titan, a moon of Saturn, and on Europa and Callisto, which orbit Jupiter—three satellites that scientists believe may have promising habitats for life. Mathematical models indicate that at least some of this vagabond debris still harbored living microbes. The asteroid may have sown life throughout the solar system, even as it ravaged life on Earth. [Continue reading…]

Astronomers say it’s time to start taking the search for E.T. seriously

Science News reports:



The group is writing a series of papers arguing that scientists should be searching the universe for “technosignatures” — any sign of alien technology, from radio signals to waste heat. The hope is that those papers will go into a report to Congress at the end of 2020 detailing the astronomical community’s priorities. That report, Astro 2020: Decadal Survey on Astronomy and Astrophysics, will determine which telescopes fly and which studies receive federal funding through the next decade. [Continue reading…]

China’s historic moon landing boosts rivalry with U.S.