Pluto will always be the 9th planet, I don't care what Neil Degrasse Tyson says.
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
#152Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart
#153I 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.
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).
Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart
#154Earlier quoted context omitted.
Not without an accretion disk, and why would it have one? It would've cleared it's orbit.
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 lifespan measured in nanoseconds at most.
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.
Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart
#155Earlier quoted context omitted.
I really hope it isn't true because if there's one out there, there will be others, and I'd rather not meet one in person. We don't have enough data to see whether there are unexpected instabilities in detected planetary systems. But it would be an interesting project to look for those.
They're not dangerous unless you get too close. A black hole is not a cosmic vacuum cleaner. If the Moon were suddenly transformed into a tiny black hole with the same mass, it would continue to orbit the Earth at the same distance. Ocean tides due to its gravity would continue normally. There would not be much effect except that it would no longer be visible with the naked eye and would no longer reflect the sun's l…
> you might get dangerous X-ray and gamma ray emissions from its accretion disc
There’s not enough matter nearby to feed it enough to form an accretion disc
> we could send probes to orbit it
Hitting a cm-sized black hole orbit at a lunar distance sounds insanely hard, given it’s invisible (even with occasional lensing).
Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart
#156Earlier quoted context omitted.
Why useful? Considering how hard of a time astronomers are having to simply find it it’s hard to imagine it being easy to study.
A black hole reachable in a human lifetime with ordinary chemical rockets would be an amazing laboratory for extreme physics.
What's the first thing we throw in?
Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart
#157[flagged]
Please don't complain about tangential annoyances—e.g. article or website formats, name collisions, or back-button breakage. They're too common to be interesting.
Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart
#158I 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.
700 AU is way past heliopause, firmly in the interstellar space. Same, 15 times farther than Pluto is definitely away from the Solar system "proper". It's about 100 light-hours away from Sun.
I wonder how could this object be counted as a "planet" belonging to the Solar system, even if it were the size of Jupiter. But it's an object "estimated to be 2 to 4 times the radius, and about ten times the mass of the Earth". This must be another class of celestial bodies, some jumbo-sized Oort cloud object.
Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart
#159I can clearly see the object as a bright group of pixels in the IRAS image, but I don't see a damn thing at the spot they hilight in the AKARI image. Like, are they kidding or is this a crap article with the wrong image or something?
You'd have to read the actual paper [1] to understand this. It does not appear as a physical source in the plot because of how the dataset works. The image is only for reference regarding the position.
Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart
#160Earlier quoted context omitted.
The guy killed Pluto and still he isn't done :( Seriously though, is he one of the people responsible for Pluto's demotion to dwarf planet?
Nobody killed Pluto. Back in the early 1800s children used to memorize the names of the 12 planets: Mercury, Venus, Earth, Ceres, Pallas, Juno, Vesta, Mars, Jupiter, Saturn, Uranus, and Neptune. But then in 1845 astronomers discovered Astraea, and now there were 13. In 1847 three more were discovered: Hebe, Iris, and Flora. Then Metis, Hygiea, Parthenope, and Victoria by 1850. The 100th asteroid was discovered in 186…
I think he’s referring to Mike Brown’s book “How I Killed Pluto and Why It Had It Coming”. It’s a great read.