Thursday Throughput: Gamma-ray Bursts Are Bad Edition
A mosaic image of the Neil Gehrels Swift Observatory made from images taken by the telescope.
[ThTh1] Today’s Ask an Astronomer question comes via a Facebook request: Are we in danger of being killed by a gamma ray burst?
Gamma-ray bursts (GRBs) are the biggest explosions in the universe. They are the birth pangs of black holes — either through a hypernova or the merging of two neutron stars (neutrons stars being the shriveled husks of dead massive stars). When these events go off, the blast out material along their north and south poles. The effect is that of a lighthouse — if that pole is pointed toward the Earth, we detect a flash of gamma rays — a GRB. My mission — the Neil Gehrels Swift Observatory, which just passed the 15th anniversary of her launch — studies gamma-ray bursts.
A nearby GRB could pose a severe threat. At minimum, it would cause damage to the ozone layer, a global cooling and a significant increase in surface radiation. Increased cancer rates and starvation could follow. A really close one might kill off many of the plankton in the ocean, the basis of the food chain, causing a mass die-off. The Ordovician–Silurian mass extinction event may have been caused by a GRB.
Fortunately, such events are extremely rare — maybe a few per galaxy per million years. And they may be rarer now than they were in the early universe, since most massive stars have died out. Moreover, if the GRB’s beam were pointed away from us, that would significantly minimize the damage.
The only GRB candidate nearby is the Wolf-Rayet star WR 104. This massive star is the final phases of its life and may go out as a GRB. The orientation of the system is unclear so it’s possible the jet will be oriented at Earth. But the last study indicated that was unlikely to be the case.
So, to sum up: GRBs are dangerous. They can kill. But it’s rare. There is one candidate nearby that could be dangerous. But we’re still figuring out whether it is.
[ThTh2] I’ve mentioned Starlink before and the problem that this massive network of satellites may present to ground-based astronomy. Last week, astronomers saw no less than 19 satellites pass through their field of view while they were trying to observe. And no, we can’t just build telescopes in space to account for that. It seems to me that the sky is public property and we’re witnessing a “tragedy of the commons” with companies just launching things willy-nilly. This is not only a menace to astronomy; it’s potentially a menace to space travel as well. We at least need to be having a conversation about this.
[ThTh3] Solar panels are great. But at some point, we’re going to have to talk about how much waste they produce.
[ThT4] The gorgeous and historic Yerkes Observatory may be reopening. I spent a couple of weeks there in graduate school, studying astrometry. I literally stayed in the observatory, sleeping in the “battleship”, an area with lots of bunks and little porthole windows that looked out onto gargoyles. It’s quite a thing to spend the night alone in a vast gothic century-old observatory.
[ThTh5] Was it something it said?
[ThTh6] I’ve probably mentioned the Apple Heart Study before. This could be really interesting and a boon to medical science.
[ThTh7] Well, that’s one way to save fuel on space travel.
Hahahaha check out this alternative transfer orbit to the Moon based on chaotic dynamics, it consumes almost 40% less fuel than traditional maneuvers but takes like 2 years instead of a week and looks 100% like you have no idea what you're doing pic.twitter.com/jcsECd1vHq
— Kaura (@anni_leskela) July 26, 2018
[ThTh8] Do animals sense earthquakes before they happen? No. But yes.
[ThTh9] Is this asteroid really worth quintillions of dollars?
This asteroid could be the most valuable thing in our entire Solar System. It's valued at $700 quintillion — that's many billion times more valuable than all of the money in the world today pic.twitter.com/Ky6ENK0udL
— CNET (@CNET) November 9, 2019
That rather depends on how you value things. 16 Psyche is a very metallic asteroid, possibly the core of a failed planet. It’s mostly iron and nickel but may have lots of precious metals as well. Put simply, mining the asteroid would be like mining the Earth without having to dig through all that pesky dirt and rock.
Now, it would cost many hundreds of billions of dollars to mine the asteroid. And bringing in such a huge quantity of precious metals would crash markets. But … that would also mean that metals like gold, which are incredibly useful for technology, would be incredibly cheap. It would mean that everything we buy would cost less and run better.
Mining asteroids is one of those science fiction things … at least for now. But if it ever became science fact, it would transform our economy. And it’s one of the better arguments for more space exploration. There is a NASA mission planned to rendezvous with 16 Psyche in 2026. We’ll know a lot more about the asteroid after that.
[ThTh10] I’ve mentioned the replication crisis hitting science these days. One way this is being addressed is forcing scientists to share their data in order to be published. The result of this change? Way more null results than we used to have (that is, studies that show no connection between two things). It seems that having to let others check your work makes you do the work better and publish fewer shaky claims.
[ThTh11] We live in an amazing part of space.
The 5,000 stars nearest to the Sun. pic.twitter.com/aqvg8FUQUe
— Robert McNees the Baste God (@mcnees) November 8, 2019
Click through to find a tool to explore the nearby universe.
If the culture becomes “publish your data even if there’s a null result”, this is one of the ways that I would actually accept “this research was funded by EvilBigCo Incorporated” as a criticism; because if EBCINC wants the study to show a link between mothers drinking EBCINCola and higher IQ in babies, and the study doesn’t show that, then they’d have a strong incentive to throw the data out and claim that it was never “really” studied…Report
I hope we do get there, because being able to search null results can allow people to avoid duplicating previous work that was simply discarded.Report
Mining such an asteroid wouldn’t really crash markets, since even if we moved it into a nearby orbit, mining would take time. What would happen is that low margin mines on earth would be at risk of shutting down unless we started finding ways to use up those new space based resources (such as using the materials to build habitats and ships).Report
Not just time, the cost of retrieval even from high orbit. Consider what it costs to put up a vehicle capable of bringing down a few tons of cargo safely (both for the cargo and for the planet). Truly rare stuff might be worth it. OTOH, the value of a few million tons of steel (a tiny fraction of the asteroid’s mass) in high orbit will inevitably be due its position, and bringing it down would almost certainly decrease its value.Report
Depends on the intended purpose. Get things down a gravity well is pretty easy, as long as you intend for it to stay at the bottom of the well. If it has to go down and back up again, then that is just silly. Keep it up there and figure out how to process it in situ.
Of course, that adds to the time factor. Even if we captured that monster and got it close to Earth, and started to mine it, we’d have to develop ore processing facilities in space, unless we fully intended every kg to be used on Earth. Which, again, is kinda silly, given that we have lots of mining on Earth. Mining that thing for use down here is only going to make sense if the cost of mining a given mineral on Earth exceeds the cost of sending men and machines to the asteroid.
So yeah, a rock like that isn’t going to be upsetting markets at home any time soon, and the very act of developing the technology to extract resources from that rock will mean that we’ll probably be putting the products to use up there way more than we will down here.Report
Yeah, there’s nothing quite like talking about space based metal asteroids to demonstrate emphatically how you can be a fishing brilliant scientist in one field and not know a god(ess?)damn thing about economics.
Somehow capturing a massive metal rich asteroid in earth orbit wouldn’t be an economic disaster- it’d be an economic bonanza. The enormous decrease in the costs of metal would be accompanied by a decreasing cost in the products that use those metals and a plethora of new uses for those metals. Mining those metals in space instead of sullying our Terran eco-sphere with mines would also be an enormous boon both economically and environmentally. And, let’s be real, the only way we’re going to do much of anything major in space is if we start making stuff up there. Hauling shit up out of the Terran gravity well is just insanely expensive.Report
Fun fact: My father’s dissertation was on the effects of gamma rays on the genetic structure of African Violets.Report
ThTh2: Image a one meter empty cube whose only contents were from quantum fluctuations. Imagine another one meter cube filled with all the times ground-based astronomy has won battles against enormous commercial interests. How can you distinguish the mass difference between the two cubes?
ThTh7: I once came up with a way to get from LEO to the moon with no mass expenditure at all, though I’m probably not the first to think of it. You put up two satellites in opposite orbits (one retrograde) and use a high-velocity rail gun to fire a slug to produce an impulse (the recoil is the thrust). The muzzle velocity of the gun is made to be exactly twice the orbital velocity, plus the small delta V it gives to the satellite. You fire the slug as the two satellites pass each other, and every time they cross they find that the other satellite’s slug is floating right alongside them, following the same orbit (+V -2V = -V, and -V +2V = V). So each grabs the other’s slug and reuses it.
Even though the the satellites are making constant transfer orbits, stepping their way higher and higher, the orbital math works out exactly. The trip time is limited by the delta-V per pass, and increases linearly with the number of satellites in the constellation. Using 20 satellites, 10 in each of the two orbits, lets them exchange 10 times as many slugs per orbital revolution, and thus move upwards 10 times faster.
Of course as the constellation goes higher, the orbital velocity decreases (as does the required muzzle velocity), but the number of exchanges per hour also drops, such that the technique is only very useful down in deep gravity wells. If you were trying to get to outer planets, and each exchange gave you a 50 m/sec delta V, you’d get 100 m/sec acceleration per year, and you’d need another satellite in retrograde orbit around the sun, and if you can put a satellite in that crazy retrograde orbit you wouldn’t be playing around with a cheesy slug-transfer propulsion method.
And of course the snag is coming up with a magnetic gun with sufficient muzzle velocity.Report
“hTh2: Image a one meter empty cube whose only contents were from quantum fluctuations. Imagine another one meter cube filled with all the times ground-based astronomy has won battles against enormous commercial interests. How can you distinguish the mass difference between the two cubes?”
Astronomers have won multiple battles on light pollution — both optical and radio.Report
But did it cost any real commercial money, or did it just create an excuse for a city to spend more money on a more expensive lighting product? Or take Greenbank West Virginia. How many billions a year in income did they have to forgo?
I really see no chance that astronomers will win against giant satellite constellations that will easily generate tens of billions in revenue and provide Internet access to rural African or Indian villages so they can get vital medical information.Report