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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

#221

Post by smolder »

colonial wrote: post #165
K0balt wrote: post #127

Earlier quoted context omitted.

Aside from research, it could be used to provoke time dilation, though I’m not sure how much you could get out of a basketball sized black hole.:8

If you're interested in creating time dilation, then a planetary mass black hole unfortunately won't get you any further than, well, a regular planet with the same mass. (Aside: time dilation already occurs on and around Earth. GPS satellites have to account for the fact that time runs ever so slightly slower on the ground.)

I don't think that's right except at a radius of a typical planet. At the event horizon of even a planetary mass black hole, gravity is so strong that light cant escape, and the time dilation effect should be the same as for any event horizon.

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

#222

Post by colechristensen »

Dylan16807 wrote: post #172
colechristensen wrote: post #154

Earlier quoted context omitted.

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…

Well my guess was off by an order of magnitude or ... two :)

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

#223

Post by api »

snapetom wrote: post #119
ednite wrote: post #82

Earlier quoted context omitted.

Not sure why the downvotes—if I came off wrong, my apologies. I genuinely meant it in a humoristic way. I'd honestly love to see a probe launched into a black hole.

We don't do humor here, and I'm not kidding. Humor devolves the site into useless one liners. If you want evidence of that, go to reddit and see how useful that site is these days if you want to actually research and learn something. Slashdot knew this back in the day and while funny posts got visibility, they did not add anything to a user's total karma score.

Politics is mostly soft-banned (downvoted to oblivion) for a similar reason. Most political discourse online devolves into rage bait and outrage porn and people regurgitating canned talking points.

Look at Xhitter for endless examples of this, basically the whole site now.

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

#225

Post by halgir »

StopDisinfo910 wrote: post #220
halgir wrote: post #178

Earlier quoted context omitted.

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.

> And we know that Pluto is the furthest away planet (sue me) I don't need to sue you. It's just entirely incorrect by any sane definitions of a planet. It's not the further if you include similar bodies or not a planet. As I have no interest in saving American misplaced pride (because let's not kid ourself it's about anything else), I don't see the point of spreading misinformation. > Because more people know about…

I know it's not a planet, hence my sarcastic "sue me". I suppose the self-irony didn't work too well over text. My point was that many people still know about Pluto as a body that's at the edge of many people's everyday conceptualizations of the solar system, and I argue that makes it a more useful tool for helping people intuitively understand the particular distances involved.

> Only if you were born before it was retrograded which will be less and less likely as time goes on.

I admit my age plays into it. Though I am curious about the role Pluto has in modern primary school, do you know? I understand that it now has the same technical status as Eris et al., but I think it's still a fantastic example of how scientific understanding develops and changes. Not on par with discarding heliocentricity, but a very practical example of ongoing changes still present in our own time.

> As I have no interest in saving American misplaced pride (because let's not kid ourself it's about anything else)

I don't understand how this ties into American pride (nor am I American), what did I miss?

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

#226

Post by ashoeafoot »

rkagerer wrote: post #166
NikkiA wrote: post #70

Earlier quoted context omitted.

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.

1 hour at Warp 4

Are we there yet?

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

#227

Post by wqaatwt »

Waterluvian wrote: post #134
NikkiA wrote: post #70

Earlier quoted context omitted.

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.

On its own it’s a bit of a useless number. You’d have to know how many AU Pluto is to understand context. But if you got “15x further than Pluto” you have context without needing to know any other trivia-style numbers.

AU is not exactly a trivia style number. It’s one of the most standard units of measuring distance between different bodies in space.

Also it’s not like distance to Pluto is a meaningful number either since it’s extremely variable . AU at least is fixed

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

#228

Post by cdaringe »

rkagerer wrote: post #166
NikkiA wrote: post #70

Earlier quoted context omitted.

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.

1 hour at Warp 4

Ahem, cite your sources? At low warp we’re generally BLASTING by stars!

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

#229

Post by db48x »

juped wrote: post #201
db48x wrote: post #92

Earlier quoted context omitted.

Back in the day Mercury, Venus, Earth, Ceres, Pallas, Vesta, Juno, Mars, Jupiter, Saturn, Uranus, and Neptune were the 12 planets. You could kinda consider Pluto to be the 13th planet, but in 1930 when it was discovered there were already over 1000 named asteroids. So Pluto is the 1146th planet.

Pallas and Vesta aren't gravitationally rounded, though. But then again, the Moon is (being much larger than Ceres). (It's just better numbered as planet 3-1.)

That wasn’t a requirement in 1930.

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

#230

Post by [deleted] »

nandomrumber wrote: post #143
zamadatix wrote: post #126

Earlier quoted context omitted.

They're all horrible to conceptualize because people don't commonly deal with how far even something like the Earth to the Sun is, I don't think there is any winning answer here - at least an AU is consistently defined and maybe slightly more likely to be familiar, but it's still just about as crap to be honest. Side note: Apart from AU already being defined as average distance and not current distance, the distance…

700 AU is 4 light days. Or four days travel at the speed of light, to an outside observer. Or instantaneous for anyone travelling at the speed of light.

[deleted]
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