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If SpaceX can afford to put a car into orbit around the sun as a publicity stunt during rocket testing, I wonder how much this would cost. Edit: Probably aroun

If SpaceX can afford to put a car into orbit around the sun as a publicity stunt during rocket testing, I wonder how much this would cost. Edit: Probably around $100MM: https://www.spacex.com/about/capabilities https://www.spacex.com/about/capabilities for the launch, several $100MMs for the (space based?) accelerator and spacecraft, and then a few more for operations and research. Yeah, $1 billion as described in the article seems like a good estimate: https://arxiv.org/pdf/1805.01306.pdf https://arxiv.org/pdf/1805.01306.pdf Since knowledge arising from this experiment will probably only be useful as a common good, there aren't really incentives for this to happen, unless governments decide to go through with it. NASA's 2020 budget is only $22.6 billion: https://en.wikipedia.org/wiki/Budget_of_NASA https://en.wikipedia.org/wiki/Budget_of_NASA The Apollo program cost $153 billion: https://en.wikipedia.org/wiki/Apollo_program#Costs https://en.wikipedia.org/wiki/Apollo_program#Costs Okay, this thing is ten times further away from the sun (400 AU) than Pluto (40 AU), 80 times the distance of Jupiter from the sun (5 AU), very far. Still, it's much closer than our next closest star, Proxima Centauri, which is 265612 AU away, or over 660 times the distance of Planet 9.

ramraj07 6y ago
If we get actual evidence supporting that there could indeed be a black hole within our solar system, that seems like a true opportunity to advance our knowledge of physics. The potential to study a real black hole up close seems worth massive investments given what kind of breakthroughs could he possible from it.
- lenkite 6y ago
  Also a lovely, future power-source.
  - 7373737373 6y ago
    How would this work?
    - basementcat 6y ago
      Amplified superradiant scattering is one option. https://en.wikipedia.org/wiki/Black_hole_bomb https://en.wikipedia.org/wiki/Black_hole_bomb
    - sbierwagen 6y ago
      If it's rotating, you can extract its rotational energy using the https://en.wikipedia.org/wiki/Penrose_process https://en.wikipedia.org/wiki/Penrose_process Additionally, all black holes constantly emit Hawking radiation https://en.wikipedia.org/wiki/Hawking_radiation https://en.wikipedia.org/wiki/Hawking_radiation Unfortunately for the planet 9 black hole, it only loses mass on balance it's below a certain size, about 0.007 earth mass. Primordial black holes of that size, if they exist, would be quite useful. However, they would be monumentally hard to find: the black hole above would be 62 micrometres in radius, and have an event horizon temperature of 2.93K. Assuming no changes to the cosmic microwave background, this black hole is unstable: it will eventually radiate away all its mass and disappear. You'll be waiting a while for that to happen, at 20 picowatts, it'll take 1.9e35 gigayears to die.
- codethief 6y ago
  Yes and no. I mean, how would you study a black hole of radius ~5cm without getting really close? Consider that: 1. Time dilation dictates that it would take ages for any instrument to get near the black hole, conduct measurements and send its results back to Earth. 2. Time dilation also means you would never see anything fall into the black hole. So studying the inside of the black hole is out of question, too. But arguably this is what would be required to make any breakthroughs in our understanding of black holes. 3. Tidal forces near the event horizon of such a tiny black hole would have catastrophic consequences[1] for anything (human or object) that gets too close to it. [1] https://en.wikipedia.org/wiki/Spaghettification https://en.wikipedia.org/wiki/Spaghettification
  - 7373737373 6y ago
    Wouldn't this mean that these tidal forces may (have) cause(d) highly accelerated matter to shoot through our solar system?
    - codethief 6y ago
      I assume you're referring to astrophysical jets[1] that are common with SMBHs. I'm afraid, though, I'm not familiar enough with jet physics to answer your question. A priori, the tidal forces only cause infalling matter to get shredded (and heated up). Whether a proper accretion disk together with a (significant) jet can form, given the size of the black hole, I don't know. On a related note: It'd be interesting to see in how far such a small BH would actually be capable of "sweeping [its] local neighbourhood clear of objects" like planets are (as was claimed in some comment above). Only then would I expect a significant accretion disk and, possibly, a jet. The reason the answer to this question is not obvious (at least to me) is once again the tiny size of the BH: How would anything manage to fall into the black hole, given that it's so tiny and, thus, very easy to miss? [1] https://en.wikipedia.org/wiki/Astrophysical_jet https://en.wikipedia.org/wiki/Astrophysical_jet
ganstyles 6y ago
// If SpaceX can afford to put a car into orbit around the sun as a publicity stunt during rocket testing... SpaceX had to test the rocket anyways and have some mass in the nosecone. Elon Musk, on a lark I guess, put his personal car in the nosecone as that mass. You make it sound as if they expensively launched a rocket for publicity. In really, it probably cost a negligible amount in addition to what they already had to spend for testing.
- ISL 6y ago
  It is a scientific crime that SpaceX didn't put a gravitational-reference satellite on that launch instead. A Sputnik with a radio repeater/reflector aboard or one of these https://en.wikipedia.org/wiki/LAGEOS https://en.wikipedia.org/wiki/LAGEOS would have been a gift to future generations in the form of precision gravity tests. No moving parts, can't fail, will orbit the Sun for the remainder of human-time. Only key requirement is a lot of mass and high density. Yes, launching a car into solar orbit was cool. It was also a waste of a rare opportunity.
  - NikolaeVarius 6y ago
    It was a test launch with a high chance of failure. Why the hell would they put an actual payload into it. Are you also angry that the Apollo missions didn't put "useful" things into space when they were launching hardware with sensors Putting an actual payload into the maiden flight of the Ariane 5 made into a very expensive test failure.
    - Buttons840 6y ago
      The important fact to consider here is: How much does a LAGEOS-like satellite cost? I couldn't find the answer.
  - Buttons840 6y ago
    Thanks for the interesting comment, but I have to say: Marketing helps science too. If SpaceX achieves all its goals, then perhaps the marketing stunt was worth it? Still, I wonder if Elon knew such a satellite was a possibility. I would assume yes, but I'm not sure. How much work would it take to create a LAGEOS-like satellite? Presumably they're not just lying around. I couldn't find how much the original LAGEOS satellites cost.
DarmokJalad1701 6y ago
Tbf, the only extra "cost" there was the car itself. If they didn't use the car, they would've launched a concrete block anyway to simulate a payload.
unchocked 6y ago
You're going to have deltaV problems with that approach. It's kind of like asking why can't we use a 737 to fly some rovers on the Moon. Check out the rocket equation and see what kind of mass fraction you'll need to get hundreds of km/s: https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation

ramraj07 6y ago

If we get actual evidence supporting that there could indeed be a black hole within our solar system, that seems like a true opportunity to advance our knowledge of physics. The potential to study a real black hole up close seems worth massive investments given what kind of breakthroughs could he possible from it.

lenkite 6y ago
Also a lovely, future power-source.
- 7373737373 6y ago
  How would this work?
  - basementcat 6y ago
    Amplified superradiant scattering is one option. https://en.wikipedia.org/wiki/Black_hole_bomb https://en.wikipedia.org/wiki/Black_hole_bomb
  - sbierwagen 6y ago
    If it's rotating, you can extract its rotational energy using the https://en.wikipedia.org/wiki/Penrose_process https://en.wikipedia.org/wiki/Penrose_process Additionally, all black holes constantly emit Hawking radiation https://en.wikipedia.org/wiki/Hawking_radiation https://en.wikipedia.org/wiki/Hawking_radiation Unfortunately for the planet 9 black hole, it only loses mass on balance it's below a certain size, about 0.007 earth mass. Primordial black holes of that size, if they exist, would be quite useful. However, they would be monumentally hard to find: the black hole above would be 62 micrometres in radius, and have an event horizon temperature of 2.93K. Assuming no changes to the cosmic microwave background, this black hole is unstable: it will eventually radiate away all its mass and disappear. You'll be waiting a while for that to happen, at 20 picowatts, it'll take 1.9e35 gigayears to die.
codethief 6y ago
Yes and no. I mean, how would you study a black hole of radius ~5cm without getting really close? Consider that: 1. Time dilation dictates that it would take ages for any instrument to get near the black hole, conduct measurements and send its results back to Earth. 2. Time dilation also means you would never see anything fall into the black hole. So studying the inside of the black hole is out of question, too. But arguably this is what would be required to make any breakthroughs in our understanding of black holes. 3. Tidal forces near the event horizon of such a tiny black hole would have catastrophic consequences[1] for anything (human or object) that gets too close to it. [1] https://en.wikipedia.org/wiki/Spaghettification https://en.wikipedia.org/wiki/Spaghettification
- 7373737373 6y ago
  Wouldn't this mean that these tidal forces may (have) cause(d) highly accelerated matter to shoot through our solar system?
  - codethief 6y ago
    I assume you're referring to astrophysical jets[1] that are common with SMBHs. I'm afraid, though, I'm not familiar enough with jet physics to answer your question. A priori, the tidal forces only cause infalling matter to get shredded (and heated up). Whether a proper accretion disk together with a (significant) jet can form, given the size of the black hole, I don't know. On a related note: It'd be interesting to see in how far such a small BH would actually be capable of "sweeping [its] local neighbourhood clear of objects" like planets are (as was claimed in some comment above). Only then would I expect a significant accretion disk and, possibly, a jet. The reason the answer to this question is not obvious (at least to me) is once again the tiny size of the BH: How would anything manage to fall into the black hole, given that it's so tiny and, thus, very easy to miss? [1] https://en.wikipedia.org/wiki/Astrophysical_jet https://en.wikipedia.org/wiki/Astrophysical_jet

ganstyles 6y ago

// If SpaceX can afford to put a car into orbit around the sun as a publicity stunt during rocket testing... SpaceX had to test the rocket anyways and have some mass in the nosecone. Elon Musk, on a lark I guess, put his personal car in the nosecone as that mass. You make it sound as if they expensively launched a rocket for publicity. In really, it probably cost a negligible amount in addition to what they already had to spend for testing.

ISL 6y ago
It is a scientific crime that SpaceX didn't put a gravitational-reference satellite on that launch instead. A Sputnik with a radio repeater/reflector aboard or one of these https://en.wikipedia.org/wiki/LAGEOS https://en.wikipedia.org/wiki/LAGEOS would have been a gift to future generations in the form of precision gravity tests. No moving parts, can't fail, will orbit the Sun for the remainder of human-time. Only key requirement is a lot of mass and high density. Yes, launching a car into solar orbit was cool. It was also a waste of a rare opportunity.
- NikolaeVarius 6y ago
  It was a test launch with a high chance of failure. Why the hell would they put an actual payload into it. Are you also angry that the Apollo missions didn't put "useful" things into space when they were launching hardware with sensors Putting an actual payload into the maiden flight of the Ariane 5 made into a very expensive test failure.
  - Buttons840 6y ago
    The important fact to consider here is: How much does a LAGEOS-like satellite cost? I couldn't find the answer.
- Buttons840 6y ago
  Thanks for the interesting comment, but I have to say: Marketing helps science too. If SpaceX achieves all its goals, then perhaps the marketing stunt was worth it? Still, I wonder if Elon knew such a satellite was a possibility. I would assume yes, but I'm not sure. How much work would it take to create a LAGEOS-like satellite? Presumably they're not just lying around. I couldn't find how much the original LAGEOS satellites cost.

DarmokJalad1701 6y ago

Tbf, the only extra "cost" there was the car itself. If they didn't use the car, they would've launched a concrete block anyway to simulate a payload.

unchocked 6y ago

You're going to have deltaV problems with that approach. It's kind of like asking why can't we use a 737 to fly some rovers on the Moon. Check out the rocket equation and see what kind of mass fraction you'll need to get hundreds of km/s: https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation