A magnetic filament more than 50 times the Earth’s width is erupting off the surface of the sun.
Update 4:25 p.m. EST: The mega-filament collapsed in a gorgeous cascade of hot plasma between noon and 2 p.m. EST. NASA’s Solar Dynamics Observatory captured a beautiful movie of the eruption (above). The explosion does not appear to be aimed at Earth, so we shouldn’t expect any magnetic storms or satellite troubles.
The loop of hot plasma has been snaking around the sun’s southeast limb since Dec. 4, and appears to be growing by the hour. When SDO saw it on Dec. 4, the filament was more than 250,000 miles long, about 30 times the diameter of the Earth. In the image below, taken at about 12:30 p.m. EST on Dec. 6, the loop of charged plasma stretches more than 435,000 miles, the full radius of the sun.
So far the gigantic prominence has hung suspended peacefully above the sun’s surface, but this morning it started showing signs of instability. Long filaments like this one can break apart as coronal mass ejections, releasing tons of hot, charged material into the inner solar system and potentially causing magnetic storms on Earth — although this one seems to be safe.
The image you see is in ultraviolet channels, not visible light. This prominence is an excellent target for backyard telescopes. If you capture any great sun photos in the next few days, let us know.
Images: NASA/SDO
Via spaceweather.com
It is nice knowing that there are things out there that are able to wipe off our planet just the same way you brush an ant off your arm.
Far away in the frozen outermost depths of our solar system, there might be a hidden planet four times the size of Jupiter. This secret companion to the Sun could be responsible for sending comets into the inner solar system.
This idea is an intriguing variation on the old Nemesis theory, which holds the Sun has a smaller companion star orbiting the outer reaches of the solar system. The Nemesis star was thought to be either a pint-sized red dwarf of a failed brown dwarf, and either way its movements through the Oort Cloud at the furthest edge of our solar system would cause comets to hurtle out of their obits. Some of these would hit Earth, leading to mass extinction events. The presence of Nemesis would explain why these extinctions occur in an apparently cyclical fashion.
That's the old theory, which fell apart because (among other things) it turns out Nemesis could not have a stable enough orbit to account for the regular mass extinctions, which is the main reason such an object was hypothesized in the first place. But now University of Louisiana-Lafayette astrophysicists John Matese and Daniel Whitmire have a new theory that holds a rather different kind of companion object is out in the Oort Cloud. Fittingly, they've named it Tyche, who in mythology is the good sister of the evil Nemesis.
So, why should Tyche exist? For one thing, two centuries worth of observation indicate a disproportionate amount of comets originate from the outer regions of the Oort Cloud as opposed to the areas closer to the Sun. A planet anywhere from one to four times the mass of Jupiter could be responsible for the gravitational influence that would create this imbalance. Matese points out that the probability that this effect is purely a statistical fluke is extremely small, which suggests there's something strange going on out there in the outer Oort. Tyche might also be responsible for the unusually elongated orbit of the dwarf planet Sedna.
Matese says such the discovery a planet would be a huge shock to planetary scientists:
"Most planetary scientists would not be surprised if the largest undiscovered companion was Neptune-sized or smaller, but a Jupiter-mass object would be a surprise. If the conjecture is indeed true, the important implications would relate to how it got there - touching on the early solar environment - and how it might have affected the subsequent distributions of comets and, to a lesser extent, the known planets."
If the planet exists, it would be located some 30,000 astronomical units away, meaning its distance from the Sun is 30,000 times that of Earth. It be extremely cold, with a temperature of about -73 degrees Celsius. At such a freezing temperature, Tyche would radiate no heat for us to detect, and its extreme distance would make it incredibly hard to spot. By comparison, Neptune is only 30 astronomical units away, and the Kuiper Belt is just 55 AU from the Sun.
There's some hope that we could find Tyche, however. NASA's WISE space telescope might have caught sight of Tyche before its mission ended in October. Actually, we need to hope it spotted the planet twice, as otherwise it would be impossible to corroborate its existence. If WISE, which is the most powerful infrared telescope yet built, could not detect Tyche, then it will be quite a few years before we've got a legitimate chance at seeing it again... assuming it's out there in the first place.
[via Space.com]
The universe can be a very strange place. While groundbreaking ideas such as quantum theory, relativity and even the Earth going around the Sun might be commonly accepted now, science still continues to show that the universe contains things you might find it difficult to believe, and even more difficult to get your head around.
Theoretically, the lowest temperature that can be achieved is absolute zero, exactly −273.15°C, where the motion of all particles stops completely. However, you can never actually cool something to this temperature because, in quantum mechanics, every particle has a minimum energy, called “zero-point energy,” which you cannot get below. Remarkably, this minimum energy doesn’t just apply to particles, but to any vacuum, whose energy is called “vacuum energy.” To show that this energy exists involves a rather simple experiment– take two metal plates in a vacuum, put them close together, and they will be attracted to each other. This is caused by the energy between the plates only being able to resonate at certain frequencies, while outside the plates the vacuum energy can resonate at pretty much any frequency. Because the energy outside the plates is greater than the energy between the plates, the plates are pushed towards each other. As the plates get closer together, the force increases, and at around a 10 nm separation this effect (called the Casimir effect) creates one atmosphere of pressure between them. Because the plates reduce the vacuum energy between them to below the normal zero-point energy, the space is said to have negative energy, which has some unusual properties.
One of the properties of a negative-energy vacuum is that light actually travels faster in it than it does in a normal vacuum, something that may one day allow people to travel faster than the speed of light in a kind of negative-energy vacuum bubble. Negative energy could also be used to hold open a transversible wormhole, which although theoretically possible, would collapse as soon as it was created without a means to keep it open. Negative energy also causes black holes to evaporate. Vacuum energy is often modeled as virtual particles popping into existence and annihilating. This doesn’t violate any energy conservation laws as long as the particles are annihilated shortly afterwards. However, if two particles are produced at the event horizon of a black hole, one can be moving away from the black hole, while the other is falling into it. This means they won’t be able to annihilate, so the particles both end up with negative energy. When the negative energy particle falls into the black hole, it lowers the mass of the black hole instead of adding to it, and over time particles like these will cause the black hole to evaporate completely. Because this theory was first suggested by Stephen Hawking, the particles given off by this effect (the ones that don’t fall into the black hole) are called Hawking radiation. It was the first accepted theory to unite quantum theory with general relativity, making it Hawking’s greatest scientific achievement to date.
One prediction of Einstein’s theory of general relativity is that when a large object moves, it drags the space-time around it, causing nearby objects to be pulled along as well. It can occur when a large object is moving in a straight line or is rotating, and, although the effect is very small, it has been experimentally verified. The Gravity Probe B experiment, launched in 2004, was designed to measure the space-time distortion near Earth. Although sources of interference were larger than expected, the frame-dragging effect has been measured to an uncertainty of 15%, with further analysis hoping to reduce this further.
The expected effects were very close to predictions: due to the rotation of the Earth, the probe was pulled from its orbit by around 2 meters per year, an effect purely caused by the mass of the Earth distorting the space-time surrounding it. The probe itself would not feel this extra acceleration because it is not caused by an acceleration on the probe, but rather on the space-time the probe is traveling through–analogous to a rug being pulled under a table, rather than moving the table itself.