Alpha Centauri Sucks

Latest XKCD cartoon:

I believe this is known as a “dad joke.” In any case, nothing wrong with a little mild astronomy humor. Astro-comedy? Reminds me of this quote from Douglas Adams’s The Restaurant at the End of the Universe:

The History of every major Galactic Civilization tends to pass through three distinct and recognizable phases, those of Survival, Inquiry and Sophistication, otherwise known as the How, Why, and Where phases. For instance, the first phase is characterized by the question ‘How can we eat?’ the second by the question ‘Why do we eat?’ and the third by the question ‘Where shall we have lunch?”

(See also. And.)

An awful lot of photons

NASA Fermi 5 years gamma

Or, to be precise, 4×10^84 (that’s 4 with 84 zeros): the total amount of photons emitted by stars in the entire universe.

Clemson University scientists, relying on imagery from NASA’s Fermi Gamma-ray Space Telescope, claim for the first time to have measured all of the starlight ever generated throughout the history of the observable universe.

By the numbers: According to the new data, which was published in the journal Science on Friday, the number of photons — particles of visible light — emitted by stars amounts to 4 times 10 to the 84th power.

Russia to verify moon landings

Buzz Aldrin moon July 1969

I always thought this looked fake

It’s time someone cleared this up once and for all:

The head of Russia’s Roscosmos space agency has said that a proposed Russian mission to the moon will be tasked with verifying that the American moon landings were real, though he appeared to be making a joke.

“We have set this objective to fly and verify whether they’ve been there or not,” said Dmitry Rogozin in a video posted Saturday on Twitter.

Rogozin was responding to a question about whether or not NASA actually landed on the moon nearly 50 years ago. He appeared to be joking, as he smirked and shrugged while answering. But conspiracies surrounding NASA’s moon missions are common in Russia.

The worst idea in history?

Earth laser

Or we could not

It could prove to be:

A pair of MIT researchers has proposed a radical method for making our presence known in the universe.

In a new feasibility study, the team says it could be possible to use laser technology as a beacon to attract the attention of alien astronomers, much like a planetary-scale porch light.

Using a laser focused through a huge telescope, the researchers say this ‘porch light’ could be seen from as far as 20,000 light-years away.

In a paper published in the Astrophysical Journal, the MIT team describes how a high-powered 1 to 2-megawatt laser could be aimed toward space through a 30 to 45-meter telescope to create a detectable beacon.

With this configuration, the infrared radiation from the system would be strong enough for an intelligent species to differentiate it from the sun.

Granted, this is just a feasibility study rather than an actual proposal.

I think Stephen Hawking had the right idea about contacting aliens:

“One day, we might receive a signal from a planet like this, but we should be wary of answering back,” he in the documentary, “Stephen Hawking’s Favourite Places.”

“Meeting an advanced civilization could be like Native Americans encountering Columbus. That didn’t turn out so well.”

He claimed alien life could be “rapacious marauders roaming the cosmos in search of resources to plunder, and planets to conquer and colonize.”

My concern would be catching the attention of an aggressive von Neumann probe launched by a xenophobic alien civilization. Such a probe would have a search and destroy mission to identify signs of intelligent life throughout the galaxy, and exterminate it. Aiming a giant laser beacon at space would be like announcing your position to the enemy. Sometimes you just need to lay low.

Confirmed! Monster black hole at center of Milky Way galaxy

The enormous object with a mass of millions of suns at the center of our galaxy, 26,000 light-years away from the Earth, has long been believed to be a supermassive black hole. Now we have proof:

Researchers used the European Southern Observatory’s sensitive GRAVITY instrument on the Very Large Telescope (VLT) to observe infrared radiation flares coming from the accretion disc around Sagittarius A* — the massive object at the center of our galaxy. Scientists think that most galaxies have a supermassive black hole at their center, but they’d never before had the data and observations to prove it.

To measure the effects of gravity near to a black hole, scientists needed to observe an object actually traveling close to it. They found their mark in a small star called S2 whose orbit takes it deep within Sagittarius A*’s gravity well every 16 years. As they watched, they saw three bright flares traveling around the black hole’s event horizon at about 30 percent of the speed of light — around 216 million miles per hour.

It’s exactly what Einstein’s theory of general relativity predicts would occur when a hot spot (like S2) passes close to a black hole weighing as much as 4 million suns, and the observation helps to confirm that it’s really there.

Never before have scientists observed material orbiting so close to a black hole’s event horizon.

Oh, and in case you were worried:

If the Milky was does in fact have a black hole in the center, will the entire Milky Way eventually be drawn in, (like vacuuming a sheet off of a bed), or are certain parts too far away? Is there a big sphere of empty space around a black hole?

No, the popular picture of a black hole as a huge vacuum cleaner sucking in everything around it is inaccurate. Black holes, even the one at the center of our galaxy, are very small. Only if you get very close to a black hole’s event horizon does it start pulling everything in. So no, most of the galaxy will not eventually fall into the hole. Whether black holes have empty space around them or not depends on their environment. There may be objects or gas close enough to fall in, or there may not be. Many black holes have disks of infalling material around their equators. –Dave Kornreich

Sagittarius A NASA

Supermassive black hole Sagittarius A* (Source: NASA)

Standing on an asteroid

If you could stand on the asteroid Ryugu, about 194 million miles from earth, this is what you’d see:

Asteroid Ryugu

From Space.com:

Two tiny, hopping rovers that landed on asteroid Ryugu last week have beamed back some incredible new views of the asteroid’s rocky surface.

The Japanese Aerospace Exploration Agency’s (JAXA) Hayabusa2 sample-return mission dropped the two nearly identical rovers, named Minerva-II1A and Minerva-II1B, onto the surface of Ryugu on Sept. 21. In a new video from the eyes of Minerva-II1B, you can watch the sun move across the sky as its glaring sunlight reflects off the shiny rocks that cover Ryugu’s surface.

“Please take a moment to enjoy ‘standing’ on this new world,” JAXA officials said in a statement released today (Sept. 27).

Incoming: mysterious radio bursts from distant galaxies

Australian researchers are detecting a vast number of “fast radio bursts” emanating from deep space after upgrading their telescopes, and they (the bursts, not the researchers) are brighter and closer than any we’ve spotted before. From the story:

Fast radio bursts are one of the most mysterious phenomena in the universe. They are blasts of incredible energy – equivalent to the amount released by the Sun in 80 years – that last for just a moment, and come from a mysterious source.

And no, this has absolutely nothing to do with aliens! …Wait.

Some have suggested they are being emitted by an extraterrestrial intelligence. Harvard University scientists suggested last year that they could be leaks from vast transmitters that are usually shooting at light sail ships to push them across the universe.

Those would have to be some big transmitters.

Others have suggested that less intelligent but equally spectacular causes, such as black holes or dense stars smashing into each other.

These particular bursts have traveled billions of years, from roughly halfway across the universe to reach us.

That’s fast

A supermassive black hole at the center of a distant galaxy was recently spotted sucking in matter at a speed that would probably get you pulled over on most highways:

In a paper published September 3 in the Monthly Notices of the Royal Astronomical Society, a team of researchers reported, for the first time, spotting a clump of matter falling directly into a distant black hole at nearly one-third the speed of light.

The observations, which come from the European Space Agency’s orbiting XMM-Newton X-ray observatory, are of the 40 million-solar-mass supermassive black hole at the center of the galaxy PG211+143, about one billion light-years away. PG211+143 is a Seyfert galaxy, meaning it hosts a bright, actively feeding black hole at its center pulling in gas and dust from its surroundings. By spreading the X-ray light received from that material out by wavelength, researchers led by Ken Pounds of the University of Leicester clocked a clump of matter falling into the black hole at 30 percent the speed of light — about 56,000 miles per second (90,000 kilometers per second). “We were able to follow an Earth-sized clump of matter for about a day, as it was pulled towards the black hole, accelerating to a third of the velocity of light before being swallowed up by the hole,” said Pounds in a recent press release.

Sure, 56,000 miles per second sounds fast… but you haven’t really seen fast until you’ve seen planet-sized blobs of plasma hurled from a “blazar” galaxy at more than 99% the speed of light.

Blazar galaxy

Artist’s conception of a blazar (Source)

Even more mind-crushing is the speed achieved by the “Oh-My-God particle,” a cosmic ray particle detected above Utah in 1991. It was traveling at 99.99999999999999999999951% the speed of light, which caused considerable surprise to the astrophysicists observing it. Hence the name.

A near miss

Sagittarius dwarf galaxy

Sagittarius dwarf galaxy (Hubble)

Scientists find that the Milky Way may have had a close brush with another galaxy in the relatively recent past (cosmically speaking):

A new study published Wednesday in Nature has tracked the motion of more than six million stars in our galaxy using the European Space Agency’s Gaia spacecraft. The research reveals that the Milky Way nearly collided with another nearby galaxy — called the Sagittarius dwarf galaxy — sometime in the past 300 to 900 million years. This cosmic “fender bender” set millions of stars moving like ripples on a pond, the authors say. […]

The shape wasn’t the only thing that surprised them. Scientists knew that the Milky Way has seen many collisions over its 13.5 billion year history. But they thought that was ancient history.

Observatory reopens, but I still believe in aliens

Mulder aliens

An update on that mysterious observatory closure last week is aptly summarized by the Buzzfeed headline, “New Mexico’s Solar Observatory Is Finally Reopening But The Whole Thing Is Still Pretty Weird”:

A solar observatory in the mountains of New Mexico has reopened 10 days after it was suddenly closed and its employees evacuated for a mysterious security threat, baffling locals, the internet, and whipping conspiracy theorists into a frenzy.

On Sunday, the Association of Universities for Research in Astronomy (AURA), announced that it is reopening the Sunspot Observatory, which it manages, and that employees and the residents who had been forced to leave their homes on the site are now allowed to return.

“AURA has been cooperating with an on-going law enforcement investigation of criminal activity that occurred at Sacramento Peak. During this time, we became concerned that a suspect in the investigation potentially posed a threat to the safety of local staff and residents,” Shari Lifson, an AURA spokesperson, said in a statement Sunday. “For this reason, AURA temporarily vacated the facility and ceased science activities at this location.”

The statement provided no further details on the nature of the presumed threat, or on the status of the investigation. […]

Of course, that’s just what the authorities would say if the telescope had detected aliens or an apocalyptic solar storm, isn’t it? 🤔

But even some former NSO employees and other scientists have raised questions about the mysterious shutdown, calling it “fishy” and “pretty weird.”

“Nothing like this has ever happened before at an observatory,” John Varsik, a data scientist and telescope operator at Big Bear Solar Observatory who worked at Sunspot about two decades ago, said Friday.

“It’s all very fishy,” he said.

Here’s a nice rundown of the top theories on the closure.

Perhaps we’ll learn more when the new presidential alert system is rolled out this week:

The Trump administration will send a message to all US mobile phones on Thursday, as it tests an unused alert system that warns the public about national emergencies.

Phones will make a loud tone and have a special vibration according to the Federal Emergency Management Agency (FEMA), which will send the alert.

The test message will be headlined “Presidential Alert” and will go on to read “THIS IS A TEST of the National Wireless Emergency Alert System. No action is needed.”

US mobile phone users will not be able to opt out of the test.

Are we quite sure that’s what the message will say? Because I’m predicting a very special message of a different sort… and the famous five-tone sequence from Close Encounters of the Third Kind would make for a perfect alert sound.