International Space Station Flies Over 3 Hurricanes

Residents of Hawaii are keeping a close eye on two hurricanes in the Pacific, Madeline and Lester.

And astronauts have been watching the storms, too — from a different angle.

On Tuesday, the International Space Station caught a spectacular view of both storms, as well as a powerful hurricane in the Atlantic.

The strongest storm in the video is Gaston, currently passing through the open ocean far from land. It's a Category 3 storm, with maximum sustained winds of 120 miles per hour.

The two storms in the Pacific are more worrying for earth-dwellers. Madeline, a Category 1, is expected to pass just south of Hawaii's big island before dawn on Thursday, the Central Pacific Hurricane Center says.

Residents are concerned about the risk of flooding, Bill Dorman of Hawaii Public Radio tells our Newscast unit.

Hurricane Lester — also a Category 1, currently located more than a thousand miles east of Hawaii — might threaten the islands by this weekend, though it may have weakened to a tropical storm by then.

Also on Tuesday, NASA released an animation of satellite images showing the two storms forming and swirling in the Pacific.

Meanwhile, back in the Atlantic, another storm is brewing in the Gulf of Mexico: Tropical Depression 9, which is expected to strengthen and may threaten the Florida coast, the National Hurricane Center says.

Scientists Looking For Alien Life Investigate 'Interesting' Signal From Space

Radio telescopes of the Allen Telescope Array are seen in Hat Creek, Calif.

The SETI InThey aren't saying it's alien. But they are saying it's "interesting."stitute — the private organization that looks for signals of extraterrestrial life — has announced that it is investigating reports of an unusual radio signal picked up by Russian astronomers.

The signal was detected on a much wider bandwidth than the SETI Institute uses in its searches, and the strength of the received signal was "weak," SETI Institute astronomer Seth Shostak wrote in a blog post.

It was unusual, both in its design and its "beam shape," he says.

The signal might be coming from a solar system called HD 164595, some 94 light-years away from us, Shostak wrote. It seems to be coming from that direction, at any rate.

That system has a star similar to ours. There's one known planet circling that star, about the size of Neptune and very close to the star. That planet doesn't seem like a good candidate for hosting life, but other planets might also be in the system, Shostak wrote.

But there's no guarantee that the signal is, in fact, coming from the system. And even if it is, that doesn't mean it's definitely coming from intelligent lifeforms.

Astronomer Nick Suntzeff told Ars Technica that there's a "significant chance" it could be military — that is, coming from covert satellite communications instead of beaming to us from HD 164595.

And there are "natural sources" that could conceivably cause a wide-band signal like the one detected, Shostaktold GeekWire.

Even the astronomers who first detected the signal, in May 2015, didn't immediately alert the scientific community and ask for help confirming the signal. That suggests they were not persuaded this was extraterrestrial life reaching out, he says.

And Shostak wrote on SETI's site that it's "not terribly promising" that this is a message from alien lifeforms.

So now is not the time for either delight or panic, depending on your feelings about encountering alien lifeforms.

But it is time for more investigation, Shostak says. The SETI Institute's Allen Telescope Array in California has been turned toward HD 164595 since Sunday evening, looking for a repeat of the signal.

METI International is also using a Panama-based observatory to investigate in that direction, GeekWire reports.

You might remember that in 1977, astronomers detected the "Wow" signal, an odd burst that might, possibly, have been sent by alien lifeforms. But it has never been detected again, leaving scientists with little to work with.

If things are different this time around and one of the arrays finds a repeat of the new signal, that would "immediately spur" follow-up research, Shostak writes.

In the meantime, it's prompted speculation.

Again, astronomers are cautioning that this might easily be a false alarm. But if the signal were sent from alien life in the HD 164595 system, what would that mean? There are two primary options, Shostak says.

One scenario is that the lifeforms sent a powerful signal in all directions — a "here I am" sent to the universe in general. To reach us at its current strength, that would mean the planet had access to 100 billion billion watts of energy, "hundreds of times more energy than all the sunlight falling on Earth," Shostak wrote, indicating a very advanced alien society, with capabilities far beyond ours.

Alternately, the message could have been directed at us. That's a lower energy requirement — about equal to "the total energy consumption of all mankind."

But in that case, they'd have to know we're here. The system is too far away to have picked up any TV or radar from humans on Earth, "and it's hard to understand why anyone would want to target our solar system," Shostak says.

Aliens may have sent ‘strong message’ from deep in space, scientists claim

Scientists hunting for life on other worlds have asked for 'permanent monitoring' of the star, in the hope of other messages

A car moves along the Extraterrestrial Highway near Rachel, Nevada, on the east side of Area 51 AP

A new signal has been found deep in space that could come from alien life.

The community of astronomers and scientists who scan the skies with telescopes in an attempt to find extraterrestrial life is abuzz with excitement over a “strong signal” detected deep in space that could come from an alien civilisation.

Scientists are cautioning people not to get quite too excited – at least not yet. The evidence remains preliminary and more work will need to be done to establish if it is not just a mistake, let alone whether it’s actually an extraterrestrial communication.

The message appears to have come from a nearby star, HD164595, in the constellation Hercules. That star is 95 light years away – relatively close at the scale of the universe – and almost exactly the same size as Earth.

What’s more, that same star has at least one planet, HD164595b, which is roughly the size of Neptune and has a 40-day year. It’s this planet that has people excited, since it appears that it could have the right conditions for supporting life.

The signal came to public attention after it had been noted by science fiction author Paul Gilster, who maintains a blog that looks at deep space exploration and alien life. Until then it had gone unremarked – the signal was actually detected in May last year, and was only brought to light after a presentation by the scientists who found it.

Claudio Maccone of Turin University in Italy attended a talk by the two scientists, who work at Russia’s Ratan-600 telescope. He passed that data on to Mr Gilster, who then wrote up his blog describing what had been found.

No one is claiming that this is the work of an extraterrestrial civilisation, but it is certainly worth further study,” wrote Mr Gilster on his site Centauri Dreams.

He wrote that the strength of the signal might suggest that it came from a Kardashev Type II civilisation. The Kardeshev scale indicates how advanced an alien civilisation might be: a Type I civilisation can use and store energy from a nearby star as we can, whereas a Type II civilisation can harness the energy of the entire star and would be far more advanced than mankind.

“Working out the strength of the signal, the researchers say that if it came from an isotropic beacon, it would be of a power possible only for a Kardashev Type II civilisation. If it were a narrow beam signal focused on our solar system, it would be of a power available to a Kardashev Type I civilisation,” Mr Gilster said.

He did acknowledge that the signal might have been noise rather than an actual signal. 

“The possibility of noise of one form or another cannot be ruled out, and researchers in Paris led by Jean Schneider are considering the possible microlensing of a background source by HD164595. But the signal is provocative enough that the RATAN-600 researchers are calling for permanent monitoring of this target.”

The Russian scientists who first found the signal wrote in their presentation that the probability of it being noise was low. As such, it should be permanently monitored by Seti scientists to see whether more can be learned about the star and its planet, they said.

Some at Seti – the search for extraterrestrial intelligence, which is a collective of scientists looking to find transmissions from alien life – have already squashed the possibility of alien communications.

“I was unimpressed,” wrote Eric Korpela, an astronomer who works closely on the Seti project. “Because the receivers used were making broad band measurements, there's really nothing about this 'signal' that would distinguish it from a natural radio transient”, he wrote, pointing to the fact that it could equally have been caused by a stellar flare, active galactic nucleus, microlensing of a background source, or something else entirely.

“There's also nothing that could distinguish it from a satellite passing through the telescope field of view,” he wrote in a post aimed at trying to temper the excitement . “All in all, it's relatively uninteresting from a Seti standpoint.”

Mr Korpela said that SETI@home – the project that lets people volunteer their computers to search for life elsewhere in the universe – picks up “millions of potential signals with similar characteristics, but it takes more than that to make a good candidate”. The new potential star didn’t even satisfy the minimum criterion – that it should be detected multiple times.

If it isn’t heard again then it might be something like the “WOW” signal, received in 1977. That was a powerful radio signal that came from a group of stars called Chi Sagittarii. The astronomer who discovered it, Jerry Ehman, circled it and wrote WOW next to it to mark it for future study, but the message was never detected again.

Seti scientists hope to hear more from the star by using the Allen Telescope Array, a huge system that can be used to look for messages that indicate alien intelligence. It was pointed towards the star over the weekend but has not as yet found any signal.

“However, we have not yet covered the full range of frequencies in which the signal could be located, if it’s of far narrower bandwidth than the Russian 1 GHz receiver,” Seti wrote. “We intend to completely cover this big swath of the radio dial in the next day or two. A detection, of course, would immediately spur the Seti and radio astronomy communities to do more follow-up observations.”

Seti hopes that those observations can be enough to learn more about the star system that the signal is supposedly coming from.

“So what’s the bottom line?” asked Seth Shostak, senior astronomer at Seti. “Could it be another society sending a signal our way?  Of course, that’s possible.

“However, there are many other plausible explanations for this claimed transmission, including terrestrial interference. Without a confirmation of this signal, we can only say that it’s 'interesting'.” 

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• SETI
• extraterrestrial life
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“Space Train” Concept Could Get Humans to Mars in Two Days, If Only It Would Work

Imaginactive founder Charles Bombardier released a concept for a space train that never stops: it cuts down on energy required by eliminating the acceleration and deceleration phases which take up most fuel. The Solar Express will pick up passengers and cargo at specific points where it will meet up with other smaller shuttles so it doesn't have to land (and accelerate) all over again.

SPACE TRAIN

It takes between three to six months for a probe to reach Mars from Earth. A new concept space train called Solar Express is challenging that time frame: it would, hypothetically, be able to transport people and cargo from earth to Mars in less than two days.

Imaginactive founder, Charles Bombardier, and his team aim to create Solar Express in a way were it could travel at around 1% the speed of light, which is 3,000 km (1,864 miles) per second. At this rate, a trip to the moon would only take seven hours.

The concept started out with identifying what makes space travel expensive and inefficient. “In space, the most expensive portions of travel are the acceleration and deceleration phases. The energy required for those portions is tremendous, especially for something as heavy as a space train. In addition, if you were to start hauling cargo, it would become very expensive,” he said on their website.

Solar Express plans to circumvent these inconveniences by eliminating the acceleration and deceleration phase—it will never stop once it’s up there. Instead, it will move back and forth in space as smaller capsules containing cargo and passengers dock onto it while still in motion.

Bombardier says: “once the train reached its cruising speed, its energy consumption would be minimal. That’s the idea behind the Solar Express concept. It would never stop; instead, space wagons/capsules would rendezvous with it.” The space train will use the momentum it gained from its initial launch, and rely partially on gravity thereafter, reducing the need to use fuel. It would, hypothetically, also be able to harness solar energy and pick up water from celestial bodies, which will be used by those on board and well as being converted into fuel.  

AMBITION IS THE NEW NORMAL

Seeing as this is just a concept, there are a lot of details that would still need to be figured out. Imaginactive, being a nonprofit organization dedicated to inspiring innovative, out-of-the-box concepts, encourages and welcomes innovators to think up crazy ideas—and then figure out details after. In fact, they are continuously on the lookout for more inventors and proposals are open to everyone.

To be clear, this is just an ambitious concept. The science and development to make this possible are nowhere near the levels of certainty that would be required to actually get this concept off the ground.

While the concept seems like a moonshot, at the rate space technology is developing, can we really, definitively, say it’s impossible? Besides, we’ve regularly seen science-fiction turn into reality.

A BRICS space race? 

Concept artist’s depiction of the red planet where China’s Mars rover will land [Xinhua]

Is there a space exploration race among BRICS nations?

On Sunday, India became only the fourth country in history to employ scramjet engines in the launch and propulsion of space rockets.

Scramjet technology relies on hydrogen as fuel while oxygen from the air is used as an oxidizer to burn the fuel. Combustion occurs externally while the craft is moving at supersonic speeds.

While the US has already used scramjet engines, China and Russia are also developing the technology.

India’s successful scramjet test came just four days after the China National Space Administration published images of its space probe and rover which will be part of its upcoming mission to Mars.

China plans to send a rover to Mars around 2020, and land by 2021, to explore the Red Planet and launch 150 long range carrier rockets in the next five years for its ambitious space missions.

The Administration’s director Xu Dazhe had previously said: “The Mars probe is expected to orbit the red planet, land and deploy a rover all in one mission, which is quite difficult to achieve.”

China is also planning launch a “core module” for its first space station some time around 2018, part of a plan to have a permanent manned space station in service around 2022.

In recent years, China has rapidly increased its focus on its space program.

Two weeks ago, it launched a quantum-enabled communications satellite.

The 600+ kilogram Quantum Experiments at Space Scale, or QUESS, satellite, will circle the Earth once every 90 minutes after it enters a sun-synchronous orbit at an altitude of 500 kilometers.

“In its two-year mission, QUESS is designed to establish ‘hack-proof’ quantum communications by transmitting uncrackable keys from space to the ground,” the Administration said.

China’s current space program kicked into high gear with the launch of its first moon mission and rover in December 2013. Although that mission ended earlier this August, after 31 months, it did spur a new round of lunar exploration that will culminate in another probe to be sent to the far (dark) side of the moon in 2018.

China sent its first astronaut into space in 2003, becoming the third country after Russia and the United States to achieve independent manned space travel.

China’s rapid space program development comes on the heels of earlier successes by BRICS fellow member India.

Between 2017 and 2020, India will launch the Aditya mission to study the solar corona. This part of the Sun has temperatures of over 1 million degrees, with raging solar winds that reach a velocity of up to 1,000 km a second.

In January, India successfully launched its fifth navigation satellite, joining four previous ones aimed at forming its independent navigation system. New Delhi is aiming to expand the country’s influence in the competitive $300 billion global space industry.

The IRNSS-1E is the fifth navigation satellite in the IRNSS space system, comprising seven satellites, which would be an Indian version of the American Global Positioning System (GPS).

The launch of the satellites comes in the wake of India’s very successful Mars mission of its own.

Its $73 million Mars Orbiter (MangalYaan), which was launched in November 2013 to explore the red planet’s surface features, morphology, mineralogy and search for methane in the Martian atmosphere using indigenous scientific instruments, entered its orbit in September 2014.

The mission was nothing short of historic. India became the first country to succeed on itsfirst Mars mission and also the first in Asia to reach Mars.

It’s MangalYaan Orbiter mission cost 1/9th the budget NASA spent for its own Mars mission.

NASA plans another Mars mission in 2020.

Both China and India have dedicated billions of dollars to their space programs, but their budgets are still far below the US budget estimated at $40 billion.

With their ambitious space exploration and Mars missions, China and India have become members of a select club of space-faring nations along with US, Russia, France and Japan.

Top administrative officials in Beijing said Chinese space scientists are “looking forward to cooperation with other countries, including the country’s close neighbor India”.

Jupiter: NASA's Juno space probe makes closest approach yet to solar system's largest planet

PHOTO: Juno swung within approximately 4,200 kilometres of Jupiter. (Supplied: NASA/JPL-Caltech/SwRI/MSSS)

NASA's Juno space probe has made its closest approach yet to Jupiter during the main phase of its planned mission to the gas giant, the US space agency's officials said

Travelling at 208,000 kilometres per hour, Juno swung within approximately 4,200 kilometres of the solar system's largest planet at 8:44pm last night (AEST), the closest any spacecraft has passed.

It was the first time Juno's eight scientific instruments and its camera were switched on, marking the science mission's start, officials said in a statement on NASA's website.

"This is our first opportunity to really take a close-up look at the king of our solar system and begin to figure out how he works," said Scott Bolton, Juno's principal investigator from the Southwest Research Institute in San Antonio.

Jupiter at a glance...

• Fifth planet from the Sun
• Largest planet in the solar system with a diameter of 142,984 kilometres
• Takes 11.86 Earth years to orbit the Sun
• Average of 778 million kilometres distance from the Sun
• A day lasts 10 hours.
• Orbited by at least 67 moons

Juno first swept close to Jupiter when it entered orbit around the planet early last month after a nearly five-year voyage to help study the solar system's origins.

It also sent back its first images of the planet last month as well.

However, all the probe's instruments were turned off not to interfere with its positioning as it entered the 53.5-day orbit.

Juno will now be probing Jupiter's many layers to measure their composition, magnetic field and other properties.

Scientists hope to learn the source of the planet's fierce winds and whether Jupiter is made entirely of gas or has a solid core.

They also expect to learn more about the planet's Great Red Spot, a huge storm that has raged for thousands of years.

Saturday's flyby was Juno's first chance to take pictures of Jupiter's mysterious poles.

"No other spacecraft has ever orbited Jupiter this closely, or over the poles in this fashion," said Steve Levin, Juno project scientist from NASA's Jet Propulsion Laboratory in California's Pasadena.

NASA said it will release images from the flyby late next week.

Although data from the probe is expected to reach Earth in several days, results from scientists' analysis will take longer.

"This is our first opportunity and there are bound to be surprises," Mr Levin said.

"We need to take our time to make sure our conclusions are correct."

Juno is set to make 35 more close passes by Jupiter during its main mission, scheduled to end in February 2018, when the probe will self-destruct by diving into the planet's atmosphere.

Hello, STEREO-B! NASA Regains Contact with Long-Lost Sun Probe

NASA has restored communications with the STEREO-B solar observatory, seen here in an artist's concept, after nearly four years of silence from the sun-watching spacecraft. The probe went silent on Oct. 1, 2014.

Credit: NASA

NASA has finally re-established contact with a sun-watching probe that was thought to be lost in space after it abruptly went silent in 2014.

A signal from the long-lost spacecraft, called STEREO-B, was detected Sunday evening (Aug. 21) by NASA's Deep Space Network, a collection of space tracking stations that follows the agency's space missions across the solar system and beyond. NASA scientists had kept vigil for STEREO-B, making monthly searches for the probe until it phoned home Sunday at 6:57 p.m. EDT (2257 GMT).

Right now, it's unclear how healthy the spacecraft is after drifting in space for nearly two years. NASA lost contact with it on Oct. 1, 2014, after commanding a reset from Earth. The spacecraft's twin, STEREO-A, is still working normally. [Watch: The Sun Spits Solar Fire at STEREO-B]

"The STEREO Missions Operations team plans further recovery processes to assess observatory health, re-establish attitude control, and evaluate all subsystems and instruments," NASA officials wrote in a statement.

The STEREO spacecraft twins (their name is short for Solar and Terrestrial Relations Observatory) were launched in October 2006 and were originally supposed to last until 2008. With an extended mission, however, came challenges. For example, the orbits of both STEREO spacecraft went behind the sun in 2015, for three months each.

STEREO-B was initially lost when NASA was testing a command loss timer, which is a reset triggered during solar conjunction. Conjunction was expected to happen between January and March 2015, when STEREO-B's orbit took it behind the sun, putting it out of contact with Earth.Both STEREO spacecraft have a command loss timer that resets the spacecraft every 72 hours when it is not communicating with Earth. In 2014, controllers deliberately stopped communicating with STEREO-A to test this process, and it worked perfectly after reorienting itself with respect to certain guide stars, and sending a signal to Earth.

With STEREO-B, however, the test did not play out as planned. The hard resetdid occur, and STEREO-B sent a weak signal to Earth. But the spacecraft quickly faded into silence.

Only a few packets of data made it to Earth, but from that, the team concluded in December 2015 that the inertial measurement unit (which tells the spacecraft if it is rotating, and how fast) gave incorrect information into STEREO-B's guidance computer. At the time, NASA concluded that this set the spacecraft into a spin that left its solar panels out of sunlight most of the time, making it difficult to recharge the battery.

The team could have easily fixed the issue if STEREO-B had remained in contact, but at the time, the contact was too brief to take action, NASA added in 2015.

NASA said in a statement at the time that this meant that "the spacecraft is drifting in space with incorrect information about how it's moving — a big problem for a spacecraft that needs to keep itself pointed at the sun to stay powered on."

Alien Megastructure? 'Tabby's Star' Continues to Baffle Scientists

Artist's illustration of cometary material crossing the face of a star — one possible explanation for the strange dimming exhibited by "Tabby's star."

Nearly a year after first making headlines around the world, "Tabby's star" is still guarding its secrets.

In September 2015, a team led by Yale University astronomer Tabetha Boyajian announced that a star about 1,500 light-years from Earth called KIC 8462852 had dimmed oddly and dramatically several times over the past few years.

These dimming events, which were detected by NASA's planet-hunting Kepler space telescope, were far too substantial to be caused by an orbiting planet, scientists said. (In one case, 22 percent of the star's light was blocked. For comparison, when huge Jupiter crosses the sun's face, the result is a dimming of just 1 percent or so.) [13 Ways to Hunt Intelligent Alien Life]

Boyajian and her colleagues suggested that a cloud of fragmented comets or planetary building blocks might be responsible, but other researchers noted that the signal was also consistent with a possible "alien megastructure" — perhaps a giant swarm of energy-collecting solar panels known as a Dyson sphere.

Astronomers around the world soon began studying Tabby's star with a variety of instruments, and reanalyzing old observations of the object, in an attempt to figure out what, exactly, is going on. But they have yet to solve the puzzle.

"I'd say we have no good explanation right now for what's going on with Tabby's star," Jason Wright, an astronomer at Pennsylvania State University, said earlier this month during a talk at the Search for Extraterrestrial Intelligence (SETI) Institute in Mountain View, California. "For now, it's still a mystery."

More surprises

By surrounding their sta 

with swarms of energy-collecting

 satellites, advanced civilizations

 could create Dyson spheres.

 [Read the Full Dyson Sphere

 Infographic Here.]

Credit: by Karl Tate, Infographics Artist

In fact, that mystery may have deepened over the past 12 months.For example, in January, Bradley Schaefer, a professor of physics and astronomy at Louisiana State University, determined that, in addition to the weird short-term dimming events, the brightness of Tabby's star haddropped by about 20 percent overall between 1890 and 1989. That pattern is very difficult for known natural phenomena to explain, he said.

Schaefer came to this conclusion after poring over old photographic plates of the night sky that captured Tabby's star. Other researchers suggested that the trend Schaefer saw could have been caused by changes in the instruments used to take those photos over the century-long timespan. However, a new study bolsters Schaefer's interpretation.

In the new work, Benjamin Montet (of the California Institute of Technology and the Harvard-Smithsonian Center for Astrophysics) and Joshua Simon (of the Observatories of the Carnegie Institution of Washington) reanalyzed Kepler observations of Tabby's star from 2009 through 2013. They found that the object dimmed by 3 percent over that span, with a rapid 2-percent brightness dip over one 200-day period.

"Of a sample of 193 nearby comparison stars and 355 stars with similar stellar parameters, 0.6 percent change brightness at a rate as fast as 0.341 percent [per year], and none exhibit either the rapid decline by > 2 percent or the cumulative fading by 3 percent of KIC 8462852," Montet and Simon wrote in the new study, which they uploaded to the online preprint site ArXiv on Aug. 5. "No known or proposed stellar phenomena can fully explain all aspects of the observed light curve."

Schaefer's results, combined with those of Montet and Simon, make the comet hypothesis look less and less likely, Wright said in his SETI talk.

"Why would comets, over a century, make the star dimmer?" he said. "What's going on?" [5 Bold Claims of Alien Life]

Alien megastructure?

The sustained dimming of Tabby's star is still consistent with at least some variants of the "alien megastructure" hypothesis, Wright said.

"Some people have sort of facetiously offered that perhaps this is a Dyson sphere under construction: You're seeing lots of material getting built," he said. "In just 100 years, they've blotted out 20 percent of the starlight. That seems kind of fast to me — but, you know, aliens, right?"

It's also possible that the alien megastructure — if it exists — is fully constructed, and some parts are just denser than others, Wright added.

"That would naturally make the star get brighter and dimmer, as dense parts of the swarm came around," he said. "So if I had to invoke megastructures to explain it, that seems consistent. You've got lots of panels of different shapes, different sizes, and the big ones make big dips and the little ones make little dips, and the whole swarm is sort of like a translucent screen that makes the whole thing dimmer."

But Wright and others have always stressed that the "E.T. did it" scenario is very unlikely, and that a more prosaic explanation will probably rise to the top eventually. And indeed, other recent observations throw some cold water on the alien-megastructure idea — and any other hypothesis that invokes some object or phenomenon near Tabby's star.

Any structure surrounding the star, be it alien-made or naturally occurring, would heat up and give off infrared radiation, Wright said. But he and his colleagues saw no signatures of such "waste heat" in data gathered by NASA's Wide-field Infrared Survey Explorer spacecraft. And another research team — which analyzed observations by the Submillimeter Array telescope and the Submillimeter Common-User Bolometer Array-2 instrument, both of which are in Hawaii — also came up empty.

Whatever is blocking the starlight from Tabby's star is "not surrounding the whole star — it must be along our line of sight," Wright said. "So you can do that if it's in a disk of some kind. And that hopefully will help constrain what the heck is going on."

Wright has a hunch that the answer lies far away from Tabby's star, out in the dark depths of space.

"I think I've all but abandoned circumstellar explanations, and I think now we're going to have to talk about [some] bizarre structure in the interstellar medium, and stuff like that," he said.

Still, Wright hasn't given up on the alien-megastructure hypothesis. While the lack of waste heat is "almost a fatal blow" for the idea, he said, it's still viable if the purported aliens are doing something with the waste heat — turning it into matter, for example, or converting the heat into radio waves for communication purposes.

Astronomers have already searched for such signals coming from Tabby's star using the Allen Telescope Array, a network of radio dishes in northern California operated by the SETI Institute. They found nothing. But Wright and his colleagues plan to conduct another search beginning in October; they've secured time on West Virginia's huge Green Bank Telescope for this purpose.

"This is a 1-in-300,000 object," Wright said. "People have gone looking for more, and it's the only one. So that also says you're allowed to invoke one really rare thing, because it is a rare phenomenon."

A fanciful illustration of small black holes passing through Earth

Countless tiny black holes might be hurtling through space like cosmic bullets

First, the good news: you have not been killed by a black hole. The bad news is that it’s possible the Universe is teeming with microscopic black holes that formed at the dawn of time, all of them hurtling through space like cosmic bullets.

Some could weigh nearly as much as Earth’s Moon, others an asteroid, and still more somewhere in between. Whatever their weight, most would be smaller than the period in this sentence.

If this sounds like science fiction, it could be. But perhaps not.

Astrophysicists are running out of options to explain what most of the stuff in the Universe is made of. They know roughly 80 percent of it is dark matter, which exerts a gravitational pull on the other 20 percent - 'normal' matter - yet has remained invisible to experiments for more than 80 years.

Devices in space and underground have sought out particles of dark matter for years, but have so far turned up empty.

Which is why researchers are turning to the (somewhat frightening) notion that we’re surrounded by countless black holes that formed 13.8 billion years ago.

"On the dark matter particle side of the spectrum, the range of possibilities is narrowing down quickly," Alexander Kashlinsky, a cosmologist at NASA, previously told Business Insider. "If nothing is found there, and nothing is found in the black hole theatre, then we may be in a crisis of science."

The hope and havoc of mini black holes

To be clear, physicists aren’t betting a lot chips on the existence of infinitesimal black holes. As we’ve previously reported on Business Insider, the leading hunch is that dark matter particles do exist; it’s just that this search has proven more difficult than anticipated.

And those scientists who are seeking out ancient black holes, including Kashlinsky, think they’re pretty heavy - perhaps between 20 and 100 times the mass of the Sun.

That idea even got a boost after the recent and groundbreaking discovery of gravitational waves, which two black holes of unusual size (30 solar masses) triggered when they collided.

Yet an unpublished research on 'primordial' black holes - those formed in the hot particle soup of the Big Bang, not by collapsing stars - suggests ones that are very small in diameter could exist in droves.

If these mini-black holes are real, Kashlinsky says the heaviest of them would weigh less than the Moon, yet would be shrunken down to about 0.25 millimetres in diameter, or about the width of a human hair.

Timothy Brandt, an astrophysicist at the Institute for Advanced Study, said the very lightest, asteroid-size holes would have an apparent size of less than an atom.

The reason is because black holes are so dense. In fact, beyond a certain point, pretty much any bit of matter in the Universe squeezed tightly enough will collapse beyond a gravitational point-of-no-return.

That boundary is spherical and called an event horizon, and beyond it not even photons of light - the fastest things in the Universe - can escape if they fall in.

Any black holes smaller than an asteroid probably evaporated long ago due to Hawking radiation, a fantastical consequence of the laws of nature that Stephen Hawking deduced in 1974.

So what if tiny black holes are out there - how often would they swing by, and what might they do?

"Asteroid-mass black holes, if they were all of the dark matter, might pass through Earth once a millennium or so, but would be very, very hard to detect," Brandt told Business Insider. "If you had somebody right there, they might be able to observe one."

Brandt was sceptical asteroid-size black holes would be all that dangerous, though.

And if a heavier, sub-moon-size black hole came too close?

"We certainly would notice if one passed near Earth, since it would affect the orbits of all of our satellites," he wrote in an email. "I imagine that it would mess up GPS for example."

The good news here, says Brandt, is that mini-black holes of this size would pass between Earth and the Sun once every 100 million years or so.

"We would, on average, have to wait much longer than the age of the Universe for one to pass through Earth. Though such an event is absurdly unlikely ... It would cause some havoc," he wrote.

That could definitely kill someone, Brandt noted, since it would be "a bit like a bullet, but with the damage being done by tidal forces deforming the object and generating intense heat".

Yet the scariest scenario - at least to scientists like Brandt and Kashlinsky - is what super-tiny, essentially impossible-to-detect black holes would mean for science.

"It’s possible there is no interaction of dark matter [with normal matter] except through gravity," Brandt said. "If that’s the case, we’re in trouble. We’ve never come to that point where we know something is out there but is completely invisible to our experiments."

This article was originally published by Business Insider.