The search for extraterrestrial technology finds none

The Guardian reports:

The close encounter will have to wait. Astronomers have come up empty-handed after scanning the heavens for signs of intelligent life in the most extensive search ever performed.

Researchers used ground-based telescopes to eavesdrop on 1,327 stars within 160 light years of Earth. During three years of observations they found no evidence of signals that could plausibly come from an alien civilisation.

The only signals picked up by the Green Bank telescope in West Virginia and the Parkes telescope in Australia had more Earthly origins, the scientists found, with mobile phones and other terrestrial technology providing plenty of noise, and more transient signals coming from overflying satellites.

“It’s quiet out there,” said Danny Price, an astronomer at the University of California, Berkeley, and a member of the Breakthrough Listen project, which aims to scan a million nearby stars, the entire plane of the Milky Way, and 100 neighbouring galaxies for radio and optical signals.

“We haven’t found anything in the data, but I’m certainly not giving up hope. There are still so many more stars to look at and more search approaches to consider.”

The scientists hope to spot “technosignatures”, which could reveal the presence an alien civilisation. These powerful electromagnetic signals are distinct from the various bursts of natural radiation that pour constantly through the galaxy. [Continue reading…]

Come the day that technosignatures emanating from outer space are actually detected, we shouldn’t be too quick to declare that these represent the discovery of intelligent life.

Human beings have yet to demonstrate that the creation of advanced technology is compatible with the continued existence of the biosphere on which we depend.

The development of systems that result in this organism destroying its own habitat have resulted in the creation of our own cosmically detectable technosignatures. But these signs arguably reveal more about our destructive capacities than they say about our intelligence.

Conversely, it seems eminently reasonable to suppose that the most intelligent life forms elsewhere in this galaxy might have no technosignature. They might speak so softly that from afar there is nothing to hear.

Thus, the Earth-based search for intelligent life, constrained by the instruments we use, is less a search for life than it is a search for technology.

If or when such technology is discovered, it may well be coming from a planet where the machines are still running but their creators long ago expired.

As humans, our collective tendency to equate technology with advanced life forms most often results from mistaking scale with complexity — thus fools easily become enamored with towers.

The most complex structures on this planet, however, design humans instead of being designed by humans. Thus far, nothing we have created matches the exquisite molecular complexity of the building blocks of life itself — proteins.

As a measure of the gulf that remains between life and technology, the fact that the most advanced computer systems in existence are required in an ongoing effort to model protein folding surely tells why we should remain more in awe of life itself than we are in the lifeless tools we have created to study it.

Trump: ‘we are going back to the Moon’ but ‘NASA should NOT be talking about going to the Moon.’ Huh?

May 13, 2019:


June 7, 2019:

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?

Born out of a cosmic explosion 13.8 billion years ago, the universe rapidly inflated and then cooled, it is still expanding at an increasing rate and mostly made up of unknown dark matter and dark energy … right?

This well-known story is usually taken as a self-evident scientific fact, despite the relative lack of empirical evidence—and despite a steady crop of discrepancies arising with observations of the distant 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:

Astronomers using NASA’s Hubble Space Telescope say they have crossed an important threshold in revealing a discrepancy between the two key techniques for measuring the universe’s expansion rate. The recent study strengthens the case that new theories may be needed to explain the forces that have shaped the cosmos.

A brief recap: The universe is getting bigger every second. The space between galaxies is stretching, like dough rising in the oven. But how fast is the universe expanding? As Hubble and other telescopes seek to answer this question, they have run into an intriguing difference between what scientists predict and what they observe.

Hubble measurements suggest a faster expansion rate in the modern universe than expected, based on how the universe appeared more than 13 billion years ago. These measurements of the early universe come from the European Space Agency’s Planck satellite. This discrepancy has been identified in scientific papers over the last several years, but it has been unclear whether differences in measurement techniques are to blame, or whether the difference could result from unlucky measurements.

The latest Hubble data lower the possibility that the discrepancy is only a fluke to 1 in 100,000. This is a significant gain from an earlier estimate, less than a year ago, of a chance of 1 in 3,000.

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:

Earth may already have been visited by an object from outside our solar system — a meteor that burned up in the planet’s atmosphere in 2014, astronomers claim. If confirmed, it would be the first known interstellar object to have entered the atmosphere.

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:

Methane gas periodically wafts into the atmosphere of Mars; that notion, once considered implausible and perplexing, is now widely accepted by planetary scientists.

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.

The presence of methane is significant because the gas decays quickly. Calculations indicate that sunlight and chemical reactions in the thin Martian atmosphere would break up the molecules within a few hundred years, so any methane detected must have been created recently. [Continue reading…]

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

Douglas Preston writes:

If, on a certain evening about sixty-­six million years ago, you had stood somewhere in North America and looked up at the sky, you would have soon made out what appeared to be a star. If you watched for an hour or two, the star would have seemed to grow in brightness, although it barely moved. That’s because it was not a star but an asteroid, and it was headed directly for Earth at about forty-five thousand miles an hour. Sixty hours later, the asteroid hit. The air in front was compressed and violently heated, and it blasted a hole through the atmosphere, generating a supersonic shock wave. The asteroid struck a shallow sea where the Yucatán peninsula is today. In that moment, the Cretaceous period ended and the Paleogene period began.

A few years ago, scientists at Los Alamos National Laboratory used what was then one of the world’s most powerful computers, the so-called Q Machine, to model the effects of the impact. The result was a slow-motion, second-by-second false-color video of the event. Within two minutes of slamming into Earth, the asteroid, which was at least six miles wide, had gouged a crater about eighteen miles deep and lofted twenty-five trillion metric tons of debris into the atmosphere. Picture the splash of a pebble falling into pond water, but on a planetary scale. When Earth’s crust rebounded, a peak higher than Mt. Everest briefly rose up. The energy released was more than that of a billion Hiroshima bombs, but the blast looked nothing like a nuclear explosion, with its signature mushroom cloud. Instead, the initial blowout formed a “rooster tail,” a gigantic jet of molten material, which exited the atmosphere, some of it fanning out over North America. Much of the material was several times hotter than the surface of the sun, and it set fire to everything within a thousand miles. In addition, an inverted cone of liquefied, superheated rock rose, spread outward as countless red-hot blobs of glass, called tektites, and blanketed the Western Hemisphere.

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…]