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Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

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Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#171

Post by bagels »

userulluipeste wrote: post #131
tiahura wrote: post #113

How can we spot planets in other galaxies when we can’t even be certain how many planets are in our solar system?

It has everything to do with the available means that we have, for now. For the record though, we haven't yet been able to spot planets in other galaxies, just in our own Milky Way. The spotted ones just happened to be there when we decided to look, twice. To spot an astral body properly sized to fit the definition of planet, which we yet suspect to orbit around our own star, we should be lucky enough to look exactly…

I thought the same, but amazingly, there are some early results that suggest a transit was observed in another galaxy:

https://science.nasa.gov/universe/exoplanets/exoplanet-disco...

https://en.wikipedia.org/wiki/Extragalactic_planet

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#172

Post by Dylan16807 »

colechristensen wrote: post #154
bobmcnamara wrote: post #139

Earlier quoted context omitted.

Hawking radiation does not require an accretion disk. Edit: with an accretion disk, I'd assume we'd have noticed it by now. Outside of that, as a black hole gets smaller, the hawking radiation wavelength should go down. It is rather weak overall, but it would be rather close. I haven't actually done the math, and, this is not my area of expertise. Would a relatively close by small black hole's hawking radiation be br…

The hawking radiation of a 9x earth mass is somewhere in the neighborhood of 0.01 K where the cosmic background is 2.7 K. It would appear to be a very tiny very cold ball. The break even point for hawking radiation vs the cosmic background is about the mass of the moon. I'm not going to do much more searching or calculation but I would be willing to bet a black hole small enough to emit xrays would have a remaining l…

> A black hole bright enough to see its hawking radiation has to be tiny and would be quite short lived with an origin of unknown mechanism.

Depends on what distance you want to see it from.

A black hole that glows as hot as an incandescent filament would have as much mass as a 250km cube of rock and it would last for 10^35 years. It would have a radius of 60nm and emit less than a microwatt.

> a black hole small enough to emit xrays

To reach the low end of xrays, 100 electron volts, we'd need a black hole 100 times smaller. It would still have 10^29 years of lifetime, and would be emitting 2 milliwatts of xrays.

To reach the high end of xrays, 100k electron volts, we'd need a black hole 100k times smaller. It would still have 10^20 years of lifetime, and would be emitting 2 kilowatts of xrays.

To go the other way around, if I calculate a black hole that has "only" 10 billion years of lifetime left, weighing a dainty 190 million tons, it would be emitting 10 gigawatts of gamma rays. At 10 gigawatts of output, it would shrink by 1 ton every 285 years. The speed of light squared is an enormous number.

https://www.vttoth.com/CMS/physics-notes/311-hawking-radiati...

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#173

Post by prox »

washadjeffmad wrote: post #153
carbocation wrote: post #136

Earlier quoted context omitted.

All 3 points (two from you and one from '8bitsrule) helped me contextualize this: * 700 times further from the Sun than the Earth * 15 times further from the Sun than Pluto * 0.01 lightyear, or 1/400th the distance to the nearest star

If the Earth is 8 lightminutes from the Sun, Planet X is 3.8 lightdays. Or, it's the difference between going for a 15 minutes walk and walking from Boston to Orlando (or San Diego to Seattle, for the West Coasters).

For us Elite Dangerous players to get a sense of scale, that’s approximately 329,472,000 light seconds.

Hutton Orbital is located approximately 6,784,404 light seconds, or 0.22 light years, so this will be 50 hours of non boosted SC.

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#174

Post by josephcsible »

prox wrote: post #173
washadjeffmad wrote: post #153

Earlier quoted context omitted.

If the Earth is 8 lightminutes from the Sun, Planet X is 3.8 lightdays. Or, it's the difference between going for a 15 minutes walk and walking from Boston to Orlando (or San Diego to Seattle, for the West Coasters).

For us Elite Dangerous players to get a sense of scale, that’s approximately 329,472,000 light seconds. Hutton Orbital is located approximately 6,784,404 light seconds, or 0.22 light years, so this will be 50 hours of non boosted SC.

> that’s approximately 329,472,000 light seconds

I think you have an extra factor of 1000 somewhere.

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#175

Post by josephcsible »

washadjeffmad wrote: post #153
carbocation wrote: post #136

Earlier quoted context omitted.

All 3 points (two from you and one from '8bitsrule) helped me contextualize this: * 700 times further from the Sun than the Earth * 15 times further from the Sun than Pluto * 0.01 lightyear, or 1/400th the distance to the nearest star

If the Earth is 8 lightminutes from the Sun, Planet X is 3.8 lightdays. Or, it's the difference between going for a 15 minutes walk and walking from Boston to Orlando (or San Diego to Seattle, for the West Coasters).

Isn't that slightly overstating it? Those pairs of cities are over 1000 miles apart, so unless you walk at 6mph, that's more than 700x as far.

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#176

Post by randomtoast »

deadbabe wrote: post #121
randomtoast wrote: post #6

I find one theory regarding Planet 9 especially interesting, and that is that it could be a primordial black hole with a Schwarzschild radius on the order of just a few centimeters. So basically, just a golf ball-sized black hole. This would explain why we can see the gravitational effects on the other objects as described in many papers, and it would also explain at the same time why we have no direct observation of…

Any chance we could use this black hole as a really powerful slingshot by getting very close right before passing the event horizon and then firing off into space?

I think one problem for such tiny black holes is the way the gravitation works on objects that come close to it. So for instance, a spaceship could or a human could not reach the event horizon of a tiny black hole in one piece, because it would be torn apart by the gravitational tides. So the question is how close can you come to the event horizon before gravitation rips you apart. My guesstimation would be not close enough to reach a meaningful percentage of c.

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#177

Post by StopDisinfo910 »

AIPedant wrote: post #11

I think “15 times further from the Sun than Pluto” is more meaningful for most readers than “700 times further from the Sun than Earth.” If it exists, it’s way way way out there.

But then why Pluto rather than Eris which is considerably further than Pluto or Sedna which is even further?

Pluto is a fairly unremarkable dwarf planet. I don’t think it really helps to compare things to it.

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#178

Post by halgir »

StopDisinfo910 wrote: post #177
AIPedant wrote: post #11

I think “15 times further from the Sun than Pluto” is more meaningful for most readers than “700 times further from the Sun than Earth.” If it exists, it’s way way way out there.

But then why Pluto rather than Eris which is considerably further than Pluto or Sedna which is even further? Pluto is a fairly unremarkable dwarf planet. I don’t think it really helps to compare things to it.

Because more people know about Pluto than Eris or Sedna. And we know that Pluto is the furthest away planet (sue me). So 15x Pluto is much easier to visualize in context of the entire solar system than 700x Earth. My cosmological knowledge is above average, but I don't know off the top of my head if 700 AU is super-duper far away or still in the range of the gas giants.

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#179

Post by SequoiaHope »

halgir wrote: post #178
StopDisinfo910 wrote: post #177

Earlier quoted context omitted.

But then why Pluto rather than Eris which is considerably further than Pluto or Sedna which is even further? Pluto is a fairly unremarkable dwarf planet. I don’t think it really helps to compare things to it.

Because more people know about Pluto than Eris or Sedna. And we know that Pluto is the furthest away planet (sue me). So 15x Pluto is much easier to visualize in context of the entire solar system than 700x Earth. My cosmological knowledge is above average, but I don't know off the top of my head if 700 AU is super-duper far away or still in the range of the gas giants.

Agree. Pluto anchors is to visualizations I can remember.

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#180

Post by dmurray »

Nevermark wrote: post #80
ck2 wrote: post #25

Earlier quoted context omitted.

There's an episode on "Space & Beyond" where they show all the planets in scale to the realworld on an actual football field. Then to show Planet 9 distance they have to get in a car and drive a few miles. That worked for me.

I have a set of twelve books by an artist, titled "Astronomical" (one book for each letter). The first page shows the sun, then the rest of the books are almost all simply black pages, but with the planets and asteroid belt entities shown with accurate distance and size scale. It communicates the scales really well, while only taking up a little over a foot of bookshelf space when not being "navigated". I have two he…

If this discovery is real, you'll need to buy another 168 books and they'll span a large bookcase or a small room.
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