General Question

tramnineteen's avatar

What would we experience if the sun suddenly did not exist?

Asked by tramnineteen (736 points ) October 4th, 2010

If the sun suddenly blinked out of existence what would people on earth experience?

As I understand it, it would take 8 minutes for the last light and gravity to reach earth. At that point we would travel in a strait line tangent to the point in our orbit we were at. BUT, what about a person relative to the earth?

Mostly interested in the effects as they relate to the lack of the sun’s gravity, not light.

Feel free to both temporarily ignore the moon or to comment on it’s involvement.

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41 Answers

ChaosCross's avatar

Well with no solar light. 99% of our plants will die, we will slowly freeze over having nothing to heat us up, and we will be forced to live underground until we outweigh our oxygen supplies due to lack of oxygen-making plant-life.

That said, we would die pretty fast.

tramnineteen's avatar

Question is regarding effects of the sun’s gravity missing, not so much the light.

Qingu's avatar

The ocean tides would be different. There’s also tides in Earth’s atmosphere, but iirc they’re due to uneven solar heating, not gravity.

I don’t think a person’s reference frame on Earth would change much beyond that, but I could be wrong.

There are theorized to be planet or planet-sized brown dwarf stars out there in interstellar/intergalactic space, that don’t orbit stars. If you landed on one of them, I don’t really see how your local sense of gravity would be significantly different than on a star-orbiting planet.

tramnineteen's avatar

Would we experience a sudden jolt when gravity stopped reaching us?

SundayKittens's avatar

I guess I midundersand gravity, does it ‘reach’ us? This is a very interesting question.

tramnineteen's avatar

Gravity is transmitted at the speed of light.

ragingloli's avatar

For 8 minutes we would be experiencing no difference.
We would not see the sun’s departure for 8 minutes, because of the limited speed of light, and we would be moving in a normal solar orbit for 8 minutes, because gravity as well is limited to the speed of light.

lillycoyote's avatar

Complete annihilation that would occur almost faster than our ability to comprehend it? That would be my guess. Though while I was composing this answer @ragingloli weighed in with the 8 minutes thing so I seem to be wrong about the “faster than our ability to comprehend it” part of my comment. Anyway, we would all be gone in a matter of minutes.

ragingloli's avatar

Also, we would not experience a jolt, because we can not feel the centrifugal force that is caused by the solar orbit, mainly because the main force we experience, Terra’s gravity, overpowers it.
Also, we would probably not freeze to death instantly, because our atmosphere stores heat (you know, the reason we do not turn into ice pillars at night) and we still have volcanic activity that can heat up our planet in limited amounts.

poisonedantidote's avatar

We would fly off in streight line at about 30.000 miles a second and never be seen again.

tramnineteen's avatar

Thanks @ragingloli

That is what I was trying to figure out. I’m curious, further. Would it be possible with precise measurement to detect a “jolt”? That is would there be a small one or none at all?

ragingloli's avatar

I am sure there would be one, but it would be so small and drowned out by gravity, that it would probably take specialised equipment to detect it.

jerv's avatar

Honestly, I think that there would be so much panic that any jolt would be ignored as we would be too busy dealing with riots and looting.

Fortunately, we have enough gravitational attraction to Earth that we wouldn’t go flying off into space

downtide's avatar

@jerv that would depend on whether the earth kept spinning or not, as it was travelling in a straight line. If it keeps spinning at the same rate, we’ll be fine (for a few hours, before we all freeze to death). If it stops, then there’ll be no gravity keeping us, or our atmosphere, down. So we’d float off and suffocate in a matter of seconds.

tramnineteen's avatar

@downtide Someone can feel free to correct me if I’m wrong but I’m pretty sure gravity has nothing to do with the earth’s rotation.

jrpowell's avatar

If the timing was right we could possibly be captured by one of the larger gaseous planets. But the odds of that happening are slim since they would be speeding away too.

marymaryquitecontrary's avatar

As to the physics of the change in forces as the sun magically disappears: The sun exerts exactly the amount of gravity upon the earth that it takes to divert the earth from a tangential path to a circular path. That’s easily calculable. The sudden release of this energy would send the earth on a tangential path, but it would also have some effect on the water on the planet. If for instance you imagine the Earth pulling suddenly upward from the sun’s orbit as the gravity is released, the oceans react by moving downward, then sloshing back upward. This effect would be experienced as tidal waves of unimaginable height, perhaps 4 or 5 mile high waves. This might actually be the most immediate danger to human life on earth. Contrary to some comments, the earth wouldn’t lose its own gravity in this scenario, nor would it cool “within a couple of hours.” We know what 8 hours of cooling without sun does to the earth, that’s called “night.” We also know what months without sun is like, that can be experienced in Alaska. The earth is a huge heat sink, and has much heat within its still molten core, so if we didn’t have the waves to worry about, the descent into dark winter would be unpleasant but survivable. Geothermal, nuclear, coal, oil and other such energy sources would still work though we’d need much more of them, and we’d all have to live like they do at polar stations. Putting a big roof over a city would do much to retain the heat and make it liveable. Then the heat that’s a waste product of lighting and transportation for instance helps to heat the space.
.

jerv's avatar

@downtide Gravity is based solely on mass.

mrentropy's avatar

You would want to wear a hat. And mittens.

CMaz's avatar

In the blink of an eye. We would burst, overcome by the vacuum of space.

SundayKittens's avatar

What would allll that look like from space? My head hurts.

marymaryquitecontrary's avatar

Burst? no way. Our planet is already floating in the vacuum of space, last I checked.

hobbitsubculture's avatar

What about other planets and bodies of matter in the solar system? If we have 8 minutes before light and gravity stop, Mercury and Venus have already lost them. How likely is a collision? What about a collision with our own moon, or with any of the asteroids in the asteroid belt, once they loose gravity?

On a local level, we would experience a completely new form of darkness. Somewhere in the world, it is day time. They’re losing the sun with no streetlights on, and no moon out.

downtide's avatar

@hobbitsubculture ooh I forgot about the asteroid belt. There would be no way to prevent collision with that. We’d just carry on the same trajectory as before, right into it. Ouch. (So would Venus and Mercury, for that matter).

CMaz's avatar

@hobbitsubculture – True. “Our planet”. But, we are in a pressurized bubble.

Our planet, spinning like a tennis ball attached to a string. Suddenly, our sun blinks out.
That “string” getting cut. As you know the tennis ball will fling away. As will the earth.

Besides the earth fracturing and breaking apart, from such sudden and great velocity. Our fragile atmosphere, in a matter of seconds, will wisp away.

Us, instantaneously, being exposed to that vacuum of space.

ragingloli's avatar

@ChazMaz
I do not think so.
Earth and its atmosphere moves at a pitiful 30km/s around Sol.
Even when Sol ceases to exist, Earth will still have the same velocity of 30 km/s, just not in an elliptical orbit, but a straight line.
There would be no sudden, large acceleration or jolt. The only thing that comes close to it would be the centrifugal force that results from the orbit around the sun vanishing. That means the the atmosphere (and everything else) on the side facing the sun would become a bit lighter and the stuff on the other side of the planet a bit heavier. Given that we can barely measure the difference in weight on either side even with the centrifugal force intact, the change in weight resulting from that centrifugal force disappearing would also be minimal. You may get a tiny little wobble in Earths atmosphere while it approaches equilibrium, which means you may feel some tiny winds, but that would be it.
Earth would not fracture or break apart, nor would the atmosphere suddenly be flung into space. And we would certainly not be suddenly exposed to the vacuum.

Sorry to burst your pressurised bubble.

CMaz's avatar

“Earth will still have the same velocity of 30 km/s”
That being established due to the great gravitational force that the sun holds on us.

I might be able to hold a dragster back with my car. Being dragged along at a couple of miles an hour.

Once I let go, that dragster will take off.
As I explained in my last example of the tennis ball and the string.

ragingloli's avatar

@ChazMaz
Your dragster analogy does not fit at all. The dragster has active propulsion, which makes it accelerate. Earth does not. All it has is its current momentum.

As for your tennis ball and string. When you spin a tennisball around it moves with a certain velocity along its orbit. When you let go of the string, the tennisball does NOT accelerate. It still moves with the SAME velocity as it had when moving in orbit.
Since neither Earth nor the Tennisball have an active mode of propulsion or are being pushed by another force, thus can not accelerate, either of those two accelerating would violate the first law of thermodynamics.

You are also ignoring Earth’s own gravitational field. The one that is responsible for the fact that you are not being flung out into space at night (or rather, moving in a straight line into space instead of being forced onto the ground) from the centrifugal force you are subjected to by moving around Sol. It is also what keeps the atmosphere on our planet.
Sol being gone and with it its centrifugal force would actually lower the strain on Earth’s structural integrity.

downtide's avatar

Even so, colliding with the asteroid belt at 30km/s is going to hurt

CMaz's avatar

“It still moves with the SAME velocity as it had when moving in orbit.”
Correct. That velocity now suddenly and abruptly going in another direction.

“You are also ignoring Earth’s own gravitational field.”
Nope. That field once getting its gravity with the assistance of the sun.

“from the centrifugal force you are subjected to by moving around Sol.”
That becoming non-existence.

“Sol being gone and with it its centrifugal force would actually lower the strain on Earth’s structural integrity.”
True. Once that abrupt change in centrifugal force is gone.

ragingloli's avatar

“Once that abrupt change in centrifugal force is gone.”
Which is not that strong to begin with. As I already explained, we can not even detect it with our senses here on earth, you weigh virtually the same on both sides of the planet. That is how weak it actually is.
It being gone will certainly not result in earth breaking apart. It will not even cause noticeable earthquakes.

CMaz's avatar

“Which is not that strong to begin with.”
Would it not the Universal Law of Gravitation apply.

mattbrowne's avatar

Earth would become a

http://en.wikipedia.org/wiki/Rogue_planet

and might eventually be caught by another star hundreds of light years away. Simple life will most likely survive and a new star might start another evolution which could lead to complex life if caught in the habitable zone, perhaps intelligent life. Otherwise our extremophile species might be caught under a huge layer of ice waiting for the star to become a red giant.

mrentropy's avatar

Surely we’d all freeze into blocks of ice and then thaw out when we reached a new star? Like that caveman movie.

mattbrowne's avatar

Yes, but this would required advanced cryotechnology.

GeorgeGee's avatar

@downtide said “ooh I forgot about the asteroid belt. There would be no way to prevent collision with that”

Actually space is very nearly empty. The emptiness of space approaches 100%. If you set the earth traveling in any direction, chances approach 100% that you would not hit anything for billions of years, if ever. A simple experiment would be to point a telescope at a random point in the sky and see what is in the dead center of the view. Chances are it’s black, but if you happen to have a star dead center, even the closest star (other than the sun), Proxima Centauri, is 4.2 light years away. The earth revolves around the sun at a speed of 5.84×10^6 miles per year, so it would move at this rate when the gravity stops, so it would take (4.2 * 5.9×10^12)/(5.84 * 10^6) years… so over 4 million years if I have the decimal point right.
And the asteroid belt is very thinly populated with objects. When spacecraft are sent through the belt, collisions aren’t even considered a significant issue; no spaceship has been hit by an asteroid when crossing the belt. Further there are only a few large objects within the asteroid belt including one dwarf planet. Other than these, any small objects would burn up upon entering the earth’s atmosphere, as they always do.

hobbitsubculture's avatar

@GeorgeGee Around 4% of the universe is made up of matter. That matter is concentrated in galaxies and galaxy clusters. While most of space is empty, the area we live in isn’t. You calculated over 4 million years until earth hits something, but that calculation is based on the distance of Proxima Centauri. A collision with something in our solar system is more likely. The chances of a spacecraft hitting an asteroid might be slim, but earth is a significantly bigger target. Plus, gravity is always attracting matter to other matter.

GeorgeGee's avatar

We are every bit as much of a target while we sit in orbit around the sun, and indeed events such as the Perseid meteor showers are regular. But those tiny bits of interstellar material streaking through our skies amount to nothing more than a brief flash of light as they burn out.

jessifer1212's avatar

Based on my knowledge of gravity (which is a force, not something that travels at the speed of light) I feel like once everything in the solar system didn’t have the Sun to keep all of the objects in orbit, the force of gravity would draw everything toward the next most massive object in the solar system, Jupiter. Or something would happen somewhat like if you are spinning an object attached to a string (where the string represents the force of gravity keeping Earth and all other objects in the solar system in orbit) and then the string were to disappear. Everything would go flying out into space, and then would eventually be drawn toward other massive objects with a strong gravitational pull.

Response moderated (Spam)
tramnineteen's avatar

@jessifer1212

Gravity is a force, it does however travel at the speed of light.

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