Few things I found interesting from our friends at Space.com:
(Split because of large size, click through to see information on intermediate mass black holes, solar tsunamis, and the smallest black hole as-yet discovered)
- Firstly, missing mass in a large globular cluster suggests a black hole dwells in the center of it. If this is true, it would suggest a black hole of intermediate mass. Basically, a “normal” black hole (don’t stress the normal, they’re anything but) would be in the range of 3 or more solar masses. The biggest of normal ones get pretty big, but before the new smallest was discovered (which we’ll get to in a moment), the smallest was about 6 solar masses. A solar mass is roughly the entire mass of the sun. I’m not sure how large black holes can get just from a star going supernova, two large stars merging, et cetera, but I would like to think a star like Eta Carinae could cause a black hole 20-50 in solar mass. Of course, 50 is probably the ungodly high end and 20 is the lower end — but I’m probably wrong. Eta Carinae was confirmed to be a double star (or so it’s said), and each star would likely be as low as 80 solar masses a piece. If Eta C were one star like previously thought, estimates ranged as incredibly high as 150 solar masses, which is a lot considering that the assumed upper limit is commonly cited at 130 solar masses. Intermediate mass black holes, on the other hand, have much more than any simple star merge, dual black hole merger, triplet merger, and so on. Theoretically, you’d find IMBHs at the center of dwarf galaxies, and they would have less mass then the several million to billion solar masses of supermassive black holes. This one is estimated around 40,000 times the suns mass, making this guy a heavy weight but nothing in comparison to other known black holes.
- Next, a solar tsunami has been spotted! No, it’s not some Edward Dames wank fantasy, but an astronomical event that is very, very cool. “When [a solar tsunami] does off, it tells you that there’s been an explosion on the sun.” says Peter Gallagher of Trinity College Dublin. Yes, that’s a direct quote from the article. So far, every solar tsunami observed has been associated with a coronal mass ejection (CME), and like said CMEs, solar tsunamis are fast. Traveling at a clip of 1 million km per hour means (faster than) in a blink of an eye it’s crossed Earth. That’s fast. Let’s first get it out of the way that CMEs can pretty much exclusively damage space-based instruments, satellites being an example. They can also kill astronauts, provided they’re not well protected, but so far that’s not been much trouble. Lesser threats include radio transmission interruption, and blackouts.
- Last is probably the most interesting so far. The smallest black hole ever discovered has been detected recently. Weighing in at 3.8 solar masses, it’s significantly smaller than the previous lightweight, which was 6.3 solar masses. That is cool. No, seriously. We’re getting close to the absolute possible (theoretical) lower limit of how small black holes can be. Well, I won’t say that, because mini-black holes, which might exist, might not, would be smaller. A lot. But there’s no evidence for them, as of late. Still, this is pretty significant news. The lower limit is speculated to be around 3 solar masses, which is very, very small. The sun, for comparison, is one solar mass (duh!). Of course, there’s always the chance that the lower limit could be smaller, estimates range from 1.7 to 2.7 solar masses, as pointed out in the article. Once you get something like a neutron star that is massive enough, it may continue to collapse straight into a black hole.
Normally, I don’t comment on Space.com articles, because they do the job so well themselves and know a lot more than myself. But this time I had to make an exception, if only because I’m a sucker for black holes (wait, what?) and finding the smallest as well as a possible intermediate one is cool. It’s also cool that solar tsunamis travel so fast, so I kind of had to point that out!