5 ms·
"literally nothing there" 1. Space is big. 2. Space is REALLY big! 3. This thing would be tiny. 4. This thing would be invisible. Combine these four togeth
by chaps 3y ago
"literally nothing there"
1. Space is big.
2. Space is REALLY big!
3. This thing would be tiny.
4. This thing would be invisible.
Combine these four together and you'll quickly realize just how difficult even scoping out the probe's requirements and such would be. Would be cool though.
- ansible 3y agoI think we would be able to detect it. We can navigate spacecraft with high accuracy. If you can get a spacecraft somewhere in the vicinity of a black hole of decent mass (like a 10km asteroid equivalent) we could probably detect changes in trajectory of the spacecraft from the gravitational attraction. Or, here's an idea, blow out a tonne of radar chaff in the vicinity of the black hole and watch for how it disperses via radar. We could also try detecting Hawking radiation that a BH should generate, though that might be pretty faint (I have not done the math).
- chaps 3y agoFriend, let me repeat: Space is BIIIIIIIIIIIIIIG.
- p1mrx 3y agoWhat if we create a time loop, launch the spacecraft in a random direction, and reset the loop if nothing is found?
- simonh 3y agoTo quantify this a bit, the search area for Planet X is in the region of many hundreds of AU from the sun. That’s many millions of cubic AU to hunt around in. That’s a lot of chaff, without even considering how we would detect and track the chaff from this far away.
- skykooler 3y agoIt's sort of the equivalent of trying to find your headphones by walking around with the bluetooth menu open on your phone and waiting to see if they pop up then they must be nearby, except all you know is that they're somewhere on Earth and you don't know where until you come within ten feet or so of them. And in reality it's even harder than that, since the surface of Earth is essentially two-dimensional as far as finding things goes, but a search for a planet would need to cover most of the volume of the greater solar system.
- kaliqt 3y agoSo essentially, we need a lot more clues to narrow this search radius down.
- deleted 3y ago[deleted]
- at_a_remove 3y agoYou are correct. At about Luna-mass, then it is hotter than the 3K cosmic background. If it is heavy enough to be a 9P candidate, it would be colder than 3K. You couldn't detect by temp. You'd have to look for a very precise spike in the EM spectrum at the electron-position annihilation energy equivalent. Despite being raised on space opera and hard-sf and having a science degree, I am pretty bearish on most space exploration. Having said that, a nearby black hole wouldn't merely be nifty. For reasons we do not understand, the event horizon stops honoring conservation of baryon number (and lepton number, and other numbers). I consider this important because replication of that would allow for direct conversion of uncharged mass to energy, just as any neutral particle crossing the event horizon has its energy (eventually) returned to us. If Hawking radiation is true (we have yet to experimentally verify it), then we know that mechanism exists. Can we do it without a black hole?
- ansible 3y agoWould a small BH have enough of an accretion disc to emit sufficient X-rays to be detectable? While the density of matter in the Oort cloud is low, it is not as low as interstellar space.
- at_a_remove 3y agoDepends on size. That size? No, no accretion disc. That kind of effect would evaporate as you scale down.
- codethief 3y agoYou might be interested in Ed Witten's paper about this exact problem: "Searching for a Black Hole in the Outer Solar System", https://arxiv.org/abs/2004.14192 https://arxiv.org/abs/2004.14192
- chaps 3y agoThanks for sharing! Some interesting things -- "And one would like to launch hundreds of spacecraft (at least) in different directions so that some would come within dozens of AU of Planet 9, rather than hundreds of AU." Their example of a neat-but-good-luck project could actually achieve the goal is [1]. The spec requires ground lasers that's powered by a 1GW nuclear power plant for propulsion. And, "According to The Economist, at least a dozen off-the-shelf technologies will need to improve by orders of magnitude." [2] [1] https://breakthroughinitiatives.org/initiative/3 https://breakthroughinitiatives.org/initiative/3 [2] https://en.wikipedia.org/wiki/Breakthrough_Starshot#Technical_challenges https://en.wikipedia.org/wiki/Breakthrough_Starshot#Technica...
- kristianp 3y agoWould gravitational lensing be usable to detect one of these tiny black holes?
- codethief 3y agoI don't think so. The black holes are, by assumption, tiny and only light passing by very very closely would experience significant lensing. Farther away, the lensing would be the same as near any other planet.