191–200 of 261 posts
I hope this turns out to be wrong. I’m still holding out for a primordial back hole Planet X. That would be soooo cool and unbelievably useful.
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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 eno…
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Ya, I know but Ceres is going to get pushed into an intersection with Mars to generate an atmosphere and a hydrological cycle .......testing on fusion rocket drives is ongoing https://newatlas.com/space/pulsar-fusion-rocket-design-slash...
Hopefully the energy released would also remelt it and restart it's magnetic field, to avoid volatile loss again.
By the way, the loss of atmosphere takes millions of years too. The popular "we must restart mars magnetic field" trope likes to omit the fact. In the end occassional replenishment of volatiles would probably be cheaper.
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Capture would be like a reverse gravitational slingshot? This planet happened to meet the sun at an angle where it lost enough energy to fall into orbit instead of slinging back out like those comets that come around on long cycles?
You don't need to lose energy to enter orbit any more than you need to lose energy too roll a ball down a hill.
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I dunno, '700 AU' gelled for me instantly, '15 times the distance to pluto' doesn't even make sense given pluto's orbit isn't anywhere near circular.
The length of 2.1 trillion Olympic swimming pools. Or 698 trillion bananas.
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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".…
As long it is orbiting the sun, i.e bound by the solar gravitational field then it is in the solar system? Also depending how elliptical the orbit, is the perigee might be much closer than 700AU, while still being further than Pluto's orbit. For all we know 700 AU is the apogee and say the perigee is 70 AU (1.4x Pluto's apogee ).
The body must also be large enough to clear other bodies in the same orbit, except at the Trojan positions (L4 and L5), to be considered as a planet. Otherwise it would just be a Trans-Neptunian Object (TNO) or a Kuiper Belt Object (KBO) at these distances.
It obviously does in this case. But this pedantic detail is rather important. It was used to demote Pluto a few years back.
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The same happened to Ceres first. To be fair, Make Ceres A Planet Again!
If planets are required to clear their orbits, what was Jupiter called while the solar system was forming? A dwarf planet? A proto planet? The entire time? Was earth not a planet shortly before and after collision with Theia? The naming pedantry seems ridiculous given that we have such a small sample size.
Hell, what's it called now? Jupiter's orbit is shared with millions of Trojans. Many of them are more than a hundred kilometers in diameter; for reference, Deimos, one of Mars' moons, has a mean radius of about 6 km.
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…
When did Planet X become planet 9? Is it because Pluto was a planet and now no longer is so the X was really a Roman numeral vs a variable (if)?
The article explains that Planet X is a possible explanation for the apparent regularity of mass extinction events. Planet 9 is a separate concept to explain the bunching of Kuiper Belt objects, like Sedna.
It. Is. Not. A. Planet. Not.