The stars disappear. How does this affect earth?

[John_Mace]

@TruCelt

IANAn astronomer - just pulling ideas from the air here.

If the galaxy just disappeared, I would think the overall movement of the solar system would change - the gravitational forces that keep us in our spiral arm movement would release, which might speed up our over all rotation (as a Solar System Group, that is.) We might not be able to detect this at all, since we’d have no point of reference. But it could be enough to allow the outer bodies to fling themselves off into space.

There would be all sorts of non-stellar material from which we could reference our movement. And, probably lots of it would start heading our way, given that our solar system would suddenly be one of the most massive things in the universe.

[Lazlo]

@yabob

Actually, in 8.6 years, we’d know there was a Sirius problem.

I lol’d.

[Beware_of_Doug]

We’d have put the question to rest about whether there’s intelligent life - hell, life - anywhere else in the universe. Suns are stars with planets. No stars, no suns - no suns, no heat - no heat, no life. No?

[Andy_L]

@Malleus_Incus_Stapes

Say there suddenly were no stars in the universe except for our sun. Maybe the Hypothetical Fairy got very bored and waved her magic wand. Does this have any effect on us and our solar system (besides putting asntronemers out of a job and confusing nocturnal animals)?
What if it’s just the stars in our galaxy?
In our arm of the Milky Way?
Just the stars right next door to us?

(Or the opposite- it’s only the neighboring stars that survive).

We’d be in a story by Greg Egan (Quarantine (Egan novel) - Wikipedia), or by Somtow Sucharitkul

[EdwardLost]

@leahcim

If Mach’s principle is true, then which reference frames are non-rotating would change, since the matter distribution of the universe suddenly switched from uniform to very lopsided as far as the Earth is concerned.

The rotation of the matter in the solar system drags local spacetime with it. The effect is very small because the rest of the matter in the universe resists it - drags back on it.

If all matter outside the solar system were to suddenly disappear, the system’s frame dragging would spread. The effect on the system would be to slowly decrease it’s net angular momentum. I’m not sure how this would play out exactly, but Jupiter’s orbit (which carries the bulk of the angular momentum) would definitely change greatly. Assuming the universe were finite, the dragging would, after billions of years, pull all of spacetime into lockstep with the solar system. The solar system would then have net zero angular momentum. Some bodies would have crashed into the sun, some flown away, and some of the remainder would orbit in opposite directions.

[TruCelt]

(Assuming the stars+dark matter disappearance) As the sole large gravitaitonal force in the universe, would our sun be on the fast-track to becoming a black hole?

[Buck_Godot]

@coremelt

To put that into perspective the earth orbits the sun at 100,000 km/h (27.8 km sec), so the 220 km/sec from the sun orbiting the galaxy suddenly changing to linear motion is pretty significant in comparison.

surely thats got to change earths orbit significantly before the earth / sun fell into a new equilibrium?

but our solar system’s orbit around the galactic core is so large that our motion is almost linear anyway. Ignoring relativistic effects, and assuming distance of 25,000ly from the core, a quick calculation shows that the centripetal acceleration required to keep us in this orbit is about 2*10^-10 m/sec^2. If this was turned off it would be not at all noticeable.

[RTFirefly]

@figure9

The new sky-show at the planetarium would be really boring.

Nah, they’d keep the old one as a nostalgia show. You could catch the concert of an '80s tribute band, or you could go to the planetarium.

@Naxos

@Malleus_Incus_Stapes

Say there suddenly were no stars in the universe except for our sun.

Impossible.

No, I just said it! “There suddenly were no stars in the universe except for our sun.” I didn’t encounter an invisible force-field that kept me from finishing the sentence, or anything like that.

[Fish_Cheer]

@EvilTOJ

It means someone finally wrote out all nine billion names.

@NoClueBoy

I have a program doing that as we spea

Complementary links

[phreesh]

Off topic, but would our sun burn out before the last rays of the most distant star reached us?

I’m asking whether the sky would ever be completely star-less if the stars were taken away tonight, but their light wasn’t blocked.

[yabob]

@phreesh

Off topic, but would our sun burn out before the last rays of the most distant star reached us?

I’m asking whether the sky would ever be completely star-less if the stars were taken away tonight, but their light wasn’t blocked.

If you are asking about objects visible to the naked eye, no, the Sun would still be here long after they disappeared. The Andromeda Galaxy is sometimes given as the most distant object visible to the naked eye - about 2.5 million light years. The Sun has several billion years left in it, if it follows the main sequence, and isn’t going to start doing much for another billion or so:

http://www.astronomy.ohio-state.edu/~pogge/Lectures/vistas97.html

Individual stars in our own galaxy are much closer. The most distant individual star visible to the naked eye may be something on the order of 10,000 - 20,000 light years.

[ZenBeam]

@EdwardLost

The rotation of the matter in the solar system drags local spacetime with it. The effect is very small because the rest of the matter in the universe resists it - drags back on it.

If all matter outside the solar system were to suddenly disappear, the system’s frame dragging would spread. The effect on the system would be to slowly decrease it’s net angular momentum. I’m not sure how this would play out exactly, but Jupiter’s orbit (which carries the bulk of the angular momentum) would definitely change greatly. Assuming the universe were finite, the dragging would, after billions of years, pull all of spacetime into lockstep with the solar system. The solar system would then have net zero angular momentum. Some bodies would have crashed into the sun, some flown away, and some of the remainder would orbit in opposite directions.

Do we know this is what would happen (assuming either classical GR, or some quantum gravity)? It seems plausible and implausible at the same time.

[JBDivmstr]

@EvilTOJ

It means someone finally wrote out all nine billion names.

@NoClueBoy

I have a program doing that as we spea

:eek:

Fish Cheer “Overhead, without any fuss, the stars were going out.”

Wow! I had forgotten how much I enjoyed Sir Clarke’s stories!

Thanks for posting the links, Fish Cheer! I’ve read many of his stories, but that was one that I haven’t had the pleasure of perusing, till now. Glad that I took the time to do so.

[Lust4Life]

@scudsucker

Won’t someone think of the astrologers?

Whole pages of magazines will be empty and devoid of content.

My god, they’d have to make stuff up !

[EdwardLost]

@EdwardLost

If all matter outside the solar system were to suddenly disappear, the system’s frame dragging would spread. The effect on the system would be to slowly decrease it’s net angular momentum. I’m not sure how this would play out exactly, but Jupiter’s orbit (which carries the bulk of the angular momentum) would definitely change greatly. Assuming the universe were finite, the dragging would, after billions of years, pull all of spacetime into lockstep with the solar system. The solar system would then have net zero angular momentum. Some bodies would have crashed into the sun, some flown away, and some of the remainder would orbit in opposite directions.

@ZenBeam

Do we know this is what would happen (assuming either classical GR, or some quantum gravity)? It seems plausible and implausible at the same time.

I don’t know the math, but it makes sense to me as a way of jibing Mach’s principle with GR. Frame dragging from all mass in the universe would result in the ST having a net rotation equal it the net rotation of the mass. But since rotation only has physical meaning wrt ST, the net angular momentum of the universe is, in effect, zero. Were the solar system the only mass in the universe it must have, eventually, net angular momentum of zero. “Eventually” because the frame dragging would take time to spread. My language is sloppy but I hope I’ve got the correct idea.

[Leo_Bloom]

Hoagy would have no consolation.

[gbiota1]

I believe lightening may be seeded by cosmic rays, so that might change.