Category: Space

No, we haven’t found an alien mega-structure yet

Over a year ago, scientists announced that they were baffled by the apparent dimming of star KIC8462852, also known as Tabby’s star. Now this is not a newly discovered star, but rather one that has been known for well over a hundred years. And that age of the star is part of what contributes to the mystery around it. See, when the star was first discovered, it was brighter than it is now. And while that isn’t unusual for a young star, KIC8462852 is understood to be a mature star – a definition that varies according to how massive the star is, but is generally millions or even billions of years.

Of course, the intarwebz came to the rescue of these poor researchers, putting forward the inescapable conclusion that what we were seeing was evidence of an alien mega-structure, most likely a Dyson Sphere. That is to say, the popular opinion online has been that the light from the star is blocked periodically by a partially built structure which surrounds star KIC8462852 and harnesses much/most of the energy output of the star, converting it to some other energy form for the advanced technology built by the aliens living near the star. Naturally, there is no other possible explanation, and clearly we’ve finally found evidence of other life in the universe.

The so-called alien megastructure hypothesis persisted longer than most extra-terrestrial-based theories, simply because scientists had few alternative ideas to explain the star’s peculiar blinking – until now. And the latest theory is almost as intriguing as the alien hypothesis.

Except, of course, that’s likely not what we’re seeing. The prevailing opinion now among experts is that we were witnessing the tail end of KIC8462852 consuming one of its own planets, brightening as a result of the added fuel, and slowly dimming back to its natural magnitude over the past hundreds or maybe thousands of years.

If KIC 8462852 did eat a planet – which is extremely rare in the space world, unless a collision pushed the planet out of its orbit – the star’s brightness would increase for a short period of 200 to 10,000 years as it burned up the planet (short in star time, that is). But once the burning was complete, the star would go back to around its original level of brightness.

So while the Dyson Sphere hypothesis is more fun, the more likely explanation is still fascinating, and gives us more information towards building a better understanding of our universe.

And Hitomi is Gone Again. For Good.

So just after I made the last post about a potential save of the Hitomi X-ray telescope, news comes that the satellite is gone for good this time. Due to a software error, the telescope was sent spinning out of control until it basically tore itself apart. Sadly, this 10-year planned mission ended up giving only a few days of data collection.

At 3:01 a.m. Japan time on March 26, the spacecraft began a preprogrammed manoeuvre to swivel from looking at the Crab Nebula to the galaxy Markarian 205. Somewhere along the way, the problems with the star tracker caused Hitomi to rely instead on another method, a set of gyroscopes, to calculate its orientation in space. But those gyroscopes were reporting, erroneously, that the spacecraft was rotating at a rate of about 20 degrees each hour. Tiny motors known as reaction wheels began to turn to counteract the supposed rotation.

100 Foot Asteroid Flew by Earth Monday Night

In what may or may not have been a close fly-by, asteroid TX68 flew by earth somewhere between 15,000 miles and 3,000,000 miles away on Monday night. First discovered Oct. 6th, 2013, the asteroid flew by then with little data collected. This made the determination of how close the current fly-by would be rather difficult, thus the broad range of distance from Earth. Scientists hope to have a better understanding of the asteroid’s path in space by the next time it comes around.

“There is no concern whatsoever regarding this asteroid — unless you were interested in seeing it with a telescope,” Paul Chodas, manager of CNEOS, assured worried Earthlings in February.

NASA has not yet determined how close TX68 came to Earth, but Rob Landis, a program officer at NASA headquarters, said if the night sky was clear in the west and over Hawaii, NASA should be able to “nail down the orbit.”

The James Webb Space Telescope

This is a massive scientific undertaking. Here’s hoping the lessons learned from the Hubble launch aren’t repeated for this telescope. The telescope will travel a million miles after launch, making repairs significantly more difficult (née impossible). james webb photoEven after it arrives at its destination, the telescope will have to unfold and cool over another month before it is operational and we will know that it will work as expected.

If you want to keep an eye on the Webb, check out NASA’s live camera view of work as it proceeds on the telescope.

Photo by NASA Goddard Photo and Video

Volcanic Explosion Tilted Mars

Billions of years ago, a volcanic explosion occurred on Mars which was so massive it actually tilted the planet:

That volcano—the Tharsis volcanic dome—is 96.3 miles by 77.7 miles. When it exploded all those years ago, it disrupted the mantle and crust of the planet (though not the rest of the interior), shifting the whole outside crust up 25 degrees. When the volcano exploded, it did so with a mass of a “billion billion” metric tons of matter, or 1,000,000,000,000,000,000 metric tons.

This explosion may have also lead ultimately to the liquid water which is now evidenced on the planet’s surface.

More on Scott Kelly

Scott Kelly is two inches taller than when he left earth a year ago. That is all.

NASA scientists already knew that Kelly would walk a little taller when he emerged from the Soyuz capsule. But he’ll have changed in other, less obvious ways, too, and that’s the whole point of his record-breaking mission. Kelly and Russian cosmonaut Mikhail Kornienko spent 342 days on the space station to help scientists measure the effects of long-term spaceflight on the human body.

OK, so I lied. That’s not all. One of the purposes of the trip was, as noted above, to study the effect of long-term spaceflight. Kelly’s twin brother submitted himself to the same battery of tests to help us better understand what happens to a person in space versus staying on earth.

The hope is that scientists can come up with a plan for protecting the men and women who might eventually journey to Mars. It’s likely that the flight to our closest neighboring world will take about nine months each way. Once a crew touches down on the sandy surface, NASA will want them to stay awhile. After all, it would be a shame to spend 18 months in a tin can for a day or two on the surface of a new planet. So it seems likely that the first Mars mission will be a multi-year commitment.

Hubble Discovers Most Distant Galaxy Yet

Galaxy gn-z11 photo
Galaxy GN-z11

First launched on April 24, 1990, the Hubble Telescope has been a boon to astronomers for decades now.

hubble photoAnd still today, we are learning new things about our universe thanks to Hubble. hubble photoNews today published on phys.org reveals that Hubble has now seen a galaxy that formed around 400 million years after the Big Bang. This is remarkable for showing us the distance Hubble is capable of resolving:

“Our spectroscopic observations reveal the galaxy to be even further away than we had originally thought, right at the distance limit of what Hubble can observe,” explains Gabriel Brammer of the Space Telescope Science Institute and second author of the study.

This puts GN-z11 at a distance that was once thought only to be reachable with the upcoming NASA/ESA/CSA James Webb Space Telescope (JWST).

The galaxy, as we can see it now in the Hubble’s photographs, is tiny compared to the size of our own Milky Way. However, it is also forming stars at a rate about 20 times what our galaxy currently does. What we’re learning from GN-z11 will likely further change our understanding of the universe’s early life:

Marijn Franx, a member of the team from the University of Leiden highlights: “The discovery of GN-z11 was a great surprise to us, as our earlier work had suggested that such bright galaxies should not exist so early in the Universe.” His colleague Ivo Labbe adds: “The discovery of GN-z11 showed us that our knowledge about the early Universe is still very restricted. How GN-z11 was created remains somewhat of a mystery for now. Probably we are seeing the first generations of stars forming around black holes?”

Photo by NASA on The Commons

Photo by NASA Goddard Photo and Video

Photo by NASA Goddard Photo and Video

Mysterious Fast Radio Bursts

Arecibo photoRecently, scientists have seen fast radio bursts coming from the same direction as one spotted in 2012. Initially announced in 2007, fast radio bursts are “millisecond chirps of radio waves pinging through the heavens” which were never seen in the same place before.

While some published research says we’ve solved the mystery of these fast radio bursts, others are not so sure:

Ultimately, astronomers need to make more measurements of these fleeting signals to figure out the puzzle. Arecibo is the most sensitive radio telescope in the world, which could be why it is the only one to have picked up repeated FRBs.

Whatever these mysterious bursts are, we have at least identified a patch of sky where they have repeated a fair number of times, and this tells us that the cause of the bursts isn’t destroyed in the process of making them.

“The fact it repeats rules out—for this object anyway—any of the models that are just one-offs, whether they involve mergers or evaporating black holes or something else,” says study co-author James Cordes, an astronomer at Cornell University. Instead, Cordes says, the more probable culprit is some sort of powerful outburst from a rotating neutron star.

The trouble is, no neutron stars have ever been seen behaving quite as strangely as the one Cordes guesses might be behind these FRBs

Photo by matt.terich