An enormous black blotch known as a “coronal hole” has been spotted spreading across the sun. Coronal holes, according to Wikipedia, are “areas where the Sun’s corona is darker, and colder, and has lower-density plasma than average because there is lower energy and gas levels.” These holes can allow high-density plasma to escape to space, which can disrupt satellite communications here on Earth.
The size and number of coronal holes peak and wane with the solar cycle, which spans 11 years.
The most recent coronal hole of a similar size opened in 2012, and was the “precursor to an extremely powerful solar storm, the most powerful one in 150 years.” That storm was considered a near-miss for Earth: according to Daniel Baker, from the University of Colorado’s Laboratory of Atmospheric and Space Physics, “If it had hit, we would still be picking up the pieces.”
We’ve all seen gorgeous, colorful images, often courtesy of the Hubble telescope, of faraway galaxies and fantastic nebulae. What most of us probably don’t realize, however, is that these aren’t true-color images — instead, they’ve typically been altered and enhanced for scientific purposes. So what does space really look like? Check out this interesting and informative video to learn!
On February 6, the largest meteor impact since the 2013 Chelyabinsk incident occurred over the southern Atlantic Ocean, yielding a fireball with an explosive force greater than 13,000 tons of TNT (13 kt) — a blast at least as energetic as the Hiroshima bomb. (By comparison, the Chelyabinsk meteor exploded over Russia with a force equal to 440,000 tons of TNT.)
Don’t worry too much, though — this headline is somewhat sensationalist. In fact, NASA keeps track of meteor impacts like this one, and it turns out that they occur on a fairly regular basis, with airbursts of this size happening every five to ten years or so, on average. To put this in a little more context, there have been six impact events during the past ten years equal or greater in size to the February 6 incident. Over this period, NASA has recorded a total of 292 meteor airbursts that have had an explosive force greater than 73 tons of TNT. (The median blast had a force equal to 230 tons of TNT.)
Unfortunately, since the February 6 event occurred in the middle of the ocean, no one was around to capture video footage of what was surely a visually-striking fireball. (Data on the February 6 event, iflscience.com reports, “were given to NASA by the U.S. government. Detecting atmospheric explosions is most likely a high priority of several branches of the U.S. military, so a fireball of such magnitude could have been easily picked up. Satellite imagery and infrasound atmospheric microphones could both be used to detect an impact like this.”)
The Chelyabinsk meteor, on the other hand, exploded over a fairly populated region and consequently was caught on film from multiple angles (you can check out some video footage of that event below). Because the Chelyabinsk meteor exploded so high in the atmosphere (at an altitude of 18.4 miles), it did little damage beyond shattering windows and scaring the bejeezus out of everyone in range.
The last meteor to inflict massive damage on the ground was the Tunguska impacter, which completely flattened 770 square miles of Siberian forest back in 1908. That meteor had a destructive force of at least 15 megatons — 1,000 times more powerful than the Hiroshima bomb.
Whenever these events happen, of course, the first question on everyone’s mind is something along the lines of, “would we be ready if a bigger one was headed our way?” The answer to this is “probably not.” However, don’t let it concern you too much — the chances of a life-threatening impact occurring during our lifetimes is infinitesimally small, and we’ve got plenty of eyes on the sky that would spot such an object well in advance.
The great thing about astrophysics is that… it’s all weird. And not much is weirder than dark matter (a “hypothetical kind of matter that cannot be seen with telescopes but accounts for most of the matter in the universe”; “one of the greatest mysteries in modern astrophysics”). Should we be surprised that the Earth is growing a dark matter mullet? Well, maybe.
While dark matter is itself unobservable, scientists can track it based on the trail it leaves. And according to a recent study published in the Astrophysical Journal, “some of those trails might come in the form of “hairy” filaments draped around Earth.” The Washington Post goes on:
If Earth is indeed wearing a dark matter toupee, it could be great news for astrophysicists.
“If we could pinpoint the location of the root of these hairs, we could potentially send a probe there and get a bonanza of data about dark matter,” lead study author Gary Prézeau of NASA’s Jet Propulsion Laboratory said in a statement.
Fine-grained streams of dark matter mixed up with matter matter are crisscrossing through our solar system as we speak. Earth’s gravity would bend these streams into dense filaments that Prézeau compares to strands of hair. The densest part of the filament — the “root,” if you will — would have a black matter density a billion times higher than the original stream.
According to the research, these roots might be as close as 600,000 miles away, with the fine tips of the filaments would reach out about twice as far.
Because these roots would boast such a dense trove of dark matter, locating and studying them could give us one of our best ever chances of detecting the mysterious stuff directly.
(Water) vortexes may be frightening — easily enough to make your palms sweat, given the
proper set of circumsances — but they pale into insignificance next to the sheer cosmic horror of black holes. Rumor has it that there’s a giant black hole lurking at the center for every galaxy (or so astronomical observations would suggest). Typically, these black holes tend to account for about 0.5% of the total mass of their respective galaxies. However, scientists have located an aberration among these aberrations:
One of the largest black holes ever seen is believed to be nearly 11.7 billion years old, forming just two billion years after the Big Bang. According to the Christian Science Monitor, the black hole is massive too; it has a mass that is equivalent to about 7 billion suns. Lead author Benny Trakhtenbrot, an astrophysicist at the Swiss Federal Institute of Technology in Zurich said that given the mass of the host galaxy, the black hole was unbelievably big[:][…] this black hole is nearly one-tenth [10%!] the mass of its host galaxy.
The findings can tell us a lot about the early universe – they suggest that the universe was smaller, denser, and much more hospitable to black holes.
Fascinating, in the same sort of way that sharks and viruses and whirlpools are fascinating. More here.
Titan, the largest moon of Saturn, is notably the only known extraterrestrial body where surface liquid exists. In its case, the liquid is not water but rather liquid methane. Titan hasn’t just got a few puddles here and there, either: it has veritable seas of liquid methane covering large parts of its surface. And at a balmy -180 degrees Celsius, they make for the perfect beach vacation!
Recently, scientists have been puzzled by th
Radar image of the Titan surface taken on 22. July 2006 from Cassini probe. We can see liquid lakes of methane in this picture. (Photo credit: Wikipedia)
e appearance of a large object in one of Titan’s methane lakes:
They spotted the object in an image taken by Nasa’s Cassini probe last year as it swung around the alien moon, more than a billion kilometres from Earth. Pictures of the same spot captured nothing before or some days later.
Little more than a white blob on a grainy image of Titan’s northern hemisphere, the sighting could be an iceberg that broke free of the shoreline, an effect of rising bubbles, or waves rolling across the normally placid lake’s surface, scientists say.
Astronomers have named the blob the “magic island” until they have a better idea what they are looking at.
Personally, I prefer to believe that the Sirens of Titan are somehow involved. At any rate, you can read more here.