Gigantic Gas Cloud on Collision Course With Our Galaxy
In case you didn't know, a huge -- like, on a galactic scale -- cloud of gas is currently speeding toward our galaxy at 700,000 mph.
In case you didn't know, a huge - like, on a galactic scale - cloud of gas is currently speeding toward our galaxy at 700,000 mph. It's full of sulfur, over 11,000 light-years long and 2,500 light-years wide, contains as much mass as a million suns... and was very likely spat out of the Milky Way while T. rex was walking the Earth.
(The dinosaur, not the British rock band.)
And it's a case of "what goes up must come down" - the cloud is on a ballistic trajectory after being blown out from our own galaxy, 70 million years ago.
Known about since 1963, the "Smith Cloud" - so-called after its discoverer Gail P. Smith - was first detected at the Dwingeloo Radio Observatory in the Netherlands. It's since been repeatedly observed in radio wavelengths with the NRAO's Green Bank Observatory in West Virginia and recently with the Hubble Space Telescope, which determined that it does in fact contain heavy elements like sulfur (contrary to some earlier analyses). This, along with its arcing trajectory, strongly indicates an origin from the star-enriched region along the outermost edges of our galaxy.
"The cloud is an example of how the galaxy is changing with time," said Andrew Fox of the Space Telescope Science Institute in Baltimore, Maryland, leader of the research team. "It's telling us that the Milky Way is a bubbling, very active place where gas can be thrown out of one part of the disk and then return back down into another."
The comet-shaped Smith Cloud contains no stars and so it's not visible in optical wavelengths. But, if it were, it would span an area of night sky as large as the constellation Orion.
When the high-velocity cloud does impact the disc of the galaxy - in about another 30 million years or so - it will be on a different (albeit neighboring) arm than the one in which our solar system resides.
The collision will likely ignite an explosion of star formation around the impact site, perhaps with enough matter and energy to create two million new solar-mass stars.
"Our galaxy is recycling its gas through clouds, the Smith Cloud being one example, and will form stars in different places than before," said Fox. "Hubble's measurements of the Smith Cloud are helping us to visualize how active the disks of galaxies are."
What actually caused the ejection of the cloud is not yet known. One intriguing suggestion is that it's a region of dark matter that collided with the Milky Way and somehow captured a clump of gas as it went.
"There are theoretical calculations suggesting that a dark matter satellite could capture gas as is passes through the Milky Way disk and that may be the amazing circumstance we are witnessing," said research co-author and long-time Smith Cloud fan Jay Lockman, an astronomer with the National Radio Astronomy Observatory (NRAO).
The findings were published in the Jan. 1, 2016 issue of The Astrophysical Journal Letters.
Composite image of the high-velocity Smith Cloud, shown in radio observations, against a visible-light image of the night sky near the constellation Aquila.
The best thing about covering news about the awesome vastness and incredible complexity of the cosmos is that, occasionally, some genuinely weird stories pop up out of nowhere.
So this year, I've taken a look back over the past 12 months to find the space stories that weren't only weird, but also genuinely stuffed with science goodness. These are my favorites.
What could be better than enjoying your favorite single malt while watching the sun set over the limb of planet Earth while living on board the International Space Station? Sounds pretty nice, but that's not quite a reality for astronauts and cosmonauts living in orbit (yet), though they do have a selection of different spirits that were delivered to the ISS this year. In the spirit of science, a Japanese whisky company sent small samples of alcoholic beverages to the orbiting outpost to see how different alcohols "mellow" in space when compared with samples stored on Earth. This experiment is a lot more than simply a publicity stunt; it is already known that the microgravity environment can influence biology and chemistry in different ways -- so why not see how it impacts the chemistry of the aging process in spirits?
I'll drink to that!
As we have no idea if there are any other living beings in the universe apart from on Earth, it would be extremely speculative if we were to, say, estimate the size of an average alien. But using statistics, a researcher went there and, using the variety of life on Earth as a guide, says that if we encounter aliens, they will more likely be "polar bear sized."
Let's hope they're not hungry...
Pulsars are rapidly-spinning balls of degenerate matter -- basically the shriveled-up, dense remains of a once more-massive star. "Dead" they may be, but that doesn't mean they don't generate an intense magnetic field. Blasting from the poles of these rapidly-spinning neutron stars are intense beams of radiation that can, if they are pointing in the right direction, can sweep past Earth, much like the beams of a lighthouse. But as they are so dense and massive, these objects have a significant impact on space-time. In research published at the beginning of 2015, astronomers described the discovery of a pulsar pair that are not only rapidly spinning, but also orbiting one another. Between them they are ripping through space-time causing it to warp. Using physics that Einstein formulated over 100 years ago, the researchers have been able to predict when one of the pulsars will be knocked off-kilter by this warping (through a process known as "geodesic precession"), making it vanish from view in the future.
OK, so this has turned into one of the most interesting head-scratchers of 2015. Soon after arriving at dwarf planet Ceres -- basically a massive asteroid in the asteroid belt, between the orbits of Mars and Jupiter -- NASA's Dawn mission noticed a very obvious bright patch of white inside a crater on the pock-marked surface. Immediately mission scientists speculated that it was most likely ice... perhaps even evidence of ice volcanoes. But it turns out that it's not that simple and we're still trying to work out what the heck it is.
Pluto's weird. Let's just leave it at that.
This is the ultimate star-crossed lovers story and it doesn't really get more extreme than this. Astronomers have discovered two massive stars -- well,
star, kinda -- that are physically touching as they orbit. They are exchanging plasma; rather than one star sucking material from the other, as they are roughly the same mass, they're simply merging. It may sound cute, but their combined mass will ultimately equal supernova death.
Black holes have never been so perplexing. One of the biggest theoretical physics battles is going on just beyond the black hole's event horizon. While, for the most part, the details are hidden in blackboard scribbles of complex mathematical equations, British physics superstar Stephen Hawking has the knack of throwing black holes into the public domain. And this year has seen another fascinating twist in the black hole "Firewall Paradox" that, while you may need a PhD in theoretical physics to fully grasp it, has made for an interesting (albeit theoretical) twist in the physical properties of a black hole's event horizon, general relativity and quantum dynamics.
By far the most popular Discovery News story this year has been this weird nugget of astronomy from NASA's Kepler Space Telescope. Kepler's mission is to seek out small worlds orbiting other stars; it's a space telescope that has profoundly changed our perspective of the sheer number (and variety) of exoplanets in our galaxy. But it has also discovered some strange stuff along the way, particularly an odd signal from Tabby's Star, some 1,500 light-years from Earth.
With the help of citizen scientists from the Planet Hunters project, a strange transit signal sparked speculation that Tabby's Star may possess evidence of an alien "megastructure." Though the signal is most likely caused by a swarm of comets, the mere mention of aliens spawned the mother of all intelligent extraterrestrial headlines, making this the most viral space story of the year.
But the weirdest is yet to come...
Since NASA's Mars rover Curiosity landed on the Red Planet in 2012, it has uncovered evidence of vast quantities of ancient water, stunning evidence for past habitable environments and a floating spoon.
By now, we all know that Curiosity has seen some strange things on the Martian surface,
. Most of these are cases of pareidolia, a psychological phenomenon when apparently random shapes (of rocks in this case) appear as familiar objects. Naturally, this often causes all manner of Martian conspiracy theories, but this image from Curiosity became a newsroom favorite as it really does look like
a floating spoon on Mars
. Of course, there's a scientific answer -- according to NASA it's a brilliant example of a "ventifact", or a rock shaped by wind erosion -- but to many of us, it will forever be remembered as the time Curiosity found a rock shaped like a floating wooden spoon.