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A dwarf planet coming within 11 AU of the sun over the next 10 years

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Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#91

Post by detaro »

chronogram wrote: post #85
mcorning wrote: post #13

For reference 1 AU (Astronomical Unit) is about 150 million km. Saturn ranges from being about 7 to 11 AU away from Earth. Voyager 1 is 152 AU away. This object is excitingly close and will be fun to study.

How come our culture didn’t base astronomical units around base 10 of our current units?

It's an old unit, so there wasn't a global standard yet, and it's exact value wasn't known for a long time, but it was still useful for ratios. E.g. if you observe the orbit time of another planet, you can tell its distance from the sun relative to the distance of Earth to Sun (1 astronomical unit) relatively accurately, even if you can't measure what it is in meters very well.

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#92

Post by sam-2727 »

pavel_lishin wrote: post #22

Aw, I thought this was going to be an extrasolar object, but it's an oort object orbiting the sun. It's also pretty small, about 1/20th the size of the moon. Huge for a comet, but smaller than Ceres.

It can definitely feel not as cool from a popular science perspective but there are many unanswered questions about the Oort Cloud so study of this object would be scientifically invaluable, even if it doesn't yield any "pop-sci" results.

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#93

Post by [deleted] »

chronogram wrote: post #85
mcorning wrote: post #13

For reference 1 AU (Astronomical Unit) is about 150 million km. Saturn ranges from being about 7 to 11 AU away from Earth. Voyager 1 is 152 AU away. This object is excitingly close and will be fun to study.

How come our culture didn’t base astronomical units around base 10 of our current units?

[deleted]

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#94

Post by mabbo »

pfdietz wrote: post #89

This is actually terrifying. That body is on a cometary orbit, and need not be stable long term. If it's chaotically pushed around by the major outer planets it might get sent into an orbit that gets into the inner solar system. And if something that size hit Earth, it would be game over for life here -- the impact would vaporize much or all of the oceans. Even an impact by something the size of comet Hale-Bopp would…

It's expected orbit will take it around 54,600 AU from the Sun. The orbital period of something that far out is in the millions of years range.

If it doesn't kill us this time, rest assured by the time it comes back we'll have done the job properly already.

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#95

Post by 8note »

CamperBob2 wrote: post #80
shkkmo wrote: post #76

Earlier quoted context omitted.

The presence of natural satellites indicates this can indeed happen. It just requires a pretty unlikely orbital configuration.

No, it doesn't. No (rocky) planet has more satellites than craters, but every planet's gravitational field is larger than its surface.

Do we know how many of those craters used to be satellites?

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#96

Post by pfdietz »

mabbo wrote: post #94
pfdietz wrote: post #89

This is actually terrifying. That body is on a cometary orbit, and need not be stable long term. If it's chaotically pushed around by the major outer planets it might get sent into an orbit that gets into the inner solar system. And if something that size hit Earth, it would be game over for life here -- the impact would vaporize much or all of the oceans. Even an impact by something the size of comet Hale-Bopp would…

It's expected orbit will take it around 54,600 AU from the Sun. The orbital period of something that far out is in the millions of years range. If it doesn't kill us this time, rest assured by the time it comes back we'll have done the job properly already.

I'm more referring to objects of this kind, not this specific object.

Threats from supercomets are not a new concern: https://academic.oup.com/mnras/article/448/1/27/990672

"A 100 km comet striking the Earth would carry ∼1000 times the energy involved in the creation of the 150 km Chicxulub crater and would presumably remove the surface biosphere"

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#97

Post by grawprog »

pfdietz wrote: post #89

This is actually terrifying. That body is on a cometary orbit, and need not be stable long term. If it's chaotically pushed around by the major outer planets it might get sent into an orbit that gets into the inner solar system. And if something that size hit Earth, it would be game over for life here -- the impact would vaporize much or all of the oceans. Even an impact by something the size of comet Hale-Bopp would…

I've always figured there's no point in worrying about giant planet destroying meteors, if one comes and we can't stop it, well we're all fucked. What can ya do at that point? If it can't be stopped and it can't be changed...well I guess we had a decent ride...at least it'll probably look cool before we're all vaporized.

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#98

Post by [deleted] »

f6v wrote: post #68
015a wrote: post #56

Earlier quoted context omitted.

Let's send some boosters out there, redirect it to earth, and make a second moon. Come on people, what ever happened to doing shit cause its fuckin' rad, do you know how cool another moon would be?!

Let’s just blow the moon up and give rise to 7 new genetically engineered races, man-fishes, and dwarves.

[deleted]

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#99

Post by Denvercoder9 »

jakeinspace wrote: post #88
Denvercoder9 wrote: post #84

Earlier quoted context omitted.

> Saturn is 1.2 billion km, roughly 7 AU That's a unit conversion error. 1.2 billion / 150 million is 8, not 7.

I believe the 1.2B km was referencing mean orbital distance from the sun, which would be 8 AU, and therefore 7 AU from earth on closest approach.

No.

Saturn's perihelion (closest distance to the Sun) is 1.35B km (9.0 AU), its aphelion (furthest distance) is 1.51B km (10.1 AU), and its mean distance is 1.43B km (9.6 AU).

Thus, at closest approach Saturn is 8 AU from Earth (since Earth orbits at an almost-constant 1 AU from the Sun).

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#100

Post by nitrogen »

chronogram wrote: post #85
mcorning wrote: post #13

For reference 1 AU (Astronomical Unit) is about 150 million km. Saturn ranges from being about 7 to 11 AU away from Earth. Voyager 1 is 152 AU away. This object is excitingly close and will be fun to study.

How come our culture didn’t base astronomical units around base 10 of our current units?

Just because nobody has said it yet and it's often assumed knowledge, one AU is supposed to be roughly the distance from Earth to the sun.
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