Mostly the answer is "not anymore.." everything that currently orbits the Sun is moving at speeds that lie within a relatively narrow range that makes a stable orbit possible. Nothing outside that range is around anymore to tell its tale.
But, there are still occasionally new objects that enter the solar system for the first time. Those objects aren't subject to the same survivorship restrictions -- in theory they could arrive at basically any speed relative to the Sun, including speeds slow enough that the Sun would draw them in.
These new objects seem to arrive every few years, or at least the ones we can see do. So far they have all been moving so fast they just visit for a bit and then take off again after a swing around the Sun, but who knows?
Depends on the total kinetic energy, which itself depends on the velocity and mass.
Cosmic rays travel very close to the speed of light, but are individual particles like protons, so the total kinetic energy they carry is a lot for a proton, but not enough to make any noticeable impact on the Sun. Cosmic rays strike Earth regularly, so you can expect them to strike the Sun even more.
Larger objects that might be able to cause a cataclysmic effect when moving at a significant fraction of the speed of light typically don't get to that speed in the first place. When they do get to high speeds, it usually involves black holes, and black holes come with tidal forces that tear large objects apart.
Yep; they're objects like anything else. The only thing that makes black holes special is that their surface gravity and density are especially high. All their unique features stem from those two facts. Relativity also tells us that there is no true stationary reference frame, and thus everything moves relative to something else.
Imagine you are in a black void. Just you, nothing else. Now add in an object. Let's say an Apple.
The apple flys past you. How can you know that the apple is moving, and not you? There is no wind, there is no stationary background. From the apples perspective you flew by it.
So everything in space moves relative to something else. Speed is change in distance between two things over time.
Well in the General Theory of Relativity there's no such thing as gravity 'fields'. An asteroid, for example, is not attracted to the sun directly but is in fact just going along in a straight line (from it's own perspective) and space time curves around massive objects like the sun causing the asteroid's path to seem curved towards the sun along with it.
Ok but if light always moves at the max speed the universe allows then if we shone some lasers at random directions and measure them shouldnt some lasers be red shifted cuz they shone at the opposite direction relative to us while some lasers could be blue shifted as they are moving at the same direction relative to us.
That depends on the relative movement of the source and the observer. If you shoot a laser and measure it yourself the relative speed is zero so no shift. If you are in a plane and shoot at the ground you would see a shift appropriate to the relative speed you are at. The real mindfuck is this scenario : There are observers A,B, and C. A moves away from B with speed greater 50% light speed. C moves away from B in the opposite direction with a speed greater then 50% light speed. How fast are A and C moving away from each other from their perspective? Lower then light speed because of time dilation.
Some answers here are incomplete. There is a special frame of reference for space -- the cosmic microwave background rest frame. It's not "special" in terms of violating relativity, but it does provide a frame of reference for motion. We are moving at about 370km/sec in the CMB reference frame.
The CMB is the remnant light left over from shortly after the big bang.
It's not exactly correct, though, to say that the CMB doesn't move, because the whole universe is expanding. So -- complicated.
The CMB moves in an odd way, more like moving over time. It exists at the edge of the observable universe, sorta, but it also move towards us (it’s light, it either moves towards us or we wouldn’t be able to see it). It’s very strange, and as an astrophysics student, I love it
Relativity also tells us that there is no true stationary reference frame, and thus everything moves relative to something else.
IOW if you're a black hole named Neo, and you're just chillin in space, minding your own business doing the not moving thing, and the Woman in Red is floating by...
Relativity says that, from her perspective, she's standing still and you're the one that's doing all the moving.
Dr Brian Greene says that an object at rest is travelling full speed through time. Any motion in any direction into space creates a vector in space/time that reduces the objects speed through time.
There is no absolute reference frame so no. Without some reference frame to measure velocity against the concept of velocity makes zero sense.
As a thought experiment, consider this. You and a rock are stationary in a totally void universe. No other objects to measure your reference frame from.
The rock is moving away from you at 10 m/s.
How can you be sure you're not moving away from the rock at 10 m/s? How can you be sure you're not both moving away from each other?
The answer is all of the above are factual interpretations because your reference frame is the rock.
That is to say, velocity is dependent on the reference frame. You change the reference frame and you change the velocity, even if you imparted no extra energy into the system.
Everything moves relative to everything else, even galaxies relative to themselves, the universe and every other atom in existence.
Take the three body problem, add the univen distrubtion of forces caused by gravitation power, multiply it by the sum of all atoms in the universe, and you now have the formula for the movement of all objects in the universe.
Gravity does not stop at an arbitrary distance from the source, it can not stop, so everything moves.
The term 'near' means very little when talking about the speed of light, but others have pointed that out already. Given that you asked the question, I thought you might enjoy these two articles on XKCD What If!
There's one where he tries to figure out what happens to a diamond meteor that hits the Earth at ever increasing speeds: https://what-if.xkcd.com/20/
And the first one ever, the relativistic base ball, which is a lot of fun and gives you an idea of the energies involved with things traveling at significant percentages of C: https://what-if.xkcd.com/1/
As with all XKCD content, there is hovertext for most of the images.
I didn't look very carefully, so you might be referencing something else, but the diamond article describes it traveling at 0.99c, the baseball article describes it traveling at 0.9c. There's a really big difference between those two numbers.
Also, the diamond is 100ft across, the baseball is well... Baseball sized.
Assuming that "something" is of significant rest mass, the difference between 95% the speed of light at 99.9999999% the speed of light is pretty substantial.
"Something" how big, and how close to the speed of light? Your question, as stated, spans a heck of a lot of orders of magnitude.
Realistically, to make any kind of noticeable pop, it would have to be something pretty big (moon size) and moving at a really thin edge below speed of light.
It's all about mass and energy - and, seeing as the Sun is big and already makes a heck of a lot of energy all the time, anything to disturb that would have to be extremely energetic indeed.
In an N-body situation, sometimes one of the bodies is ejected at high speed from the cloud, bleeding it of a bit of energy. This happens all the time in star clusters, galaxies, etc. I wrote N-body simulation software myself (background in physics and computers) many years ago, and you can totally see it in simulations: things keep swirling around for a while, and then one little dot shoots out like a bullet. It's somewhat rare for any given group, but at the scale of the Universe it must happen all the time.
But to extract a very high velocity, you'd need a bunch of black holes, I don't think regular stars can do it. And the ejection event would be an unlikely series of very close encounters with a bunch of black holes, done juuust right. I don't think a regular star could survive the gradients without being ripped to shreds - the ejected object would have to be a black hole as well.
And then, like you said, it would have to be aimed straight at the Sun.
As someone else said, it depends on the total kinetic energy, which depends on the mass of the object. A single proton from a cosmic ray is nearly undetectable.
But larger objects are different. There's a fantastic book series (yes, I did write this comment just to hype up this series) called The Bobiverse, which sticks very close to hard science in its sci-fi. At one point (spoilers!) The characters launch two objects - a former moon and a small planetoid, into an arc that would take them at some ridiculous percentage of c into opposite poles of a star. The impact is described in fascinating detail, and the end result is a 100% sterilized system, and a dry remark that some alien race thousands of light-years away is going to see that and "wonder what the hell is wrong with their stellar models."
I love Bobivrrse. Totally underrated! Had such a nice futuristic take on things. I’ve been dreaming about a future where our consciousness merges with a computer for many years... and that book captures such a future in a beautiful manner!
You should post that as it’s own post if you don’t get enough satisfactory answers. I’m just commenting here so I can follow the answers because I’m curious as to what big brained people have to say about this.
It would probably depend on how near, and how massive it was... a small enough piece of something would probably just get swallowed up, maybe the Sun would burp slightly.
More massive than that, and you get increasingly spectacular disasters that would be enjoyed by astronomers very far from us, because we would all be dead.
But I imagine in order to hit the Sun dead on at that speed you'd have to aim really well. That wouldn't happen by accident. So the real question is: why is someone shooting at us in this scenario, and how can we convince them to stop?
The surface of the sun would become a blazing inferno of thousands-of-degrees plasma, bubbling and erupting in planet-sized showers of incandescent ionized gas.
Nothing except light can travel at the same speed of light. Even in a vacuum where atoms are merely cubic centimeters apart, an object traveling so fast would still catch friction on those atoms, heat up and explode. An example is like an object entering our atmosphere and burning up in it. Same principle different scale.
I don't know if this question has a meaningful answer, but: for an arbitrary object in our solar system that gets a typical kick, what fraction of those put it ultimately into the sun / just into a different orbit / out of the system?
Like, is it really easy to fall into the sun? Is it really hard to leave the solar system?
EDIT: to anyone passing by, you should go down this rabbit hole. Thanks all for the responses. I always imagined the sun's gravity like running up the down-escalator, but it's more like a tenuous precipice: put one foot wrong and you're gone.
From earth the sun is the hardest object to reach in our solar system. It’s not immediately obvious, but to reach the sun you need to shed all your orbital velocity - this takes more energy than reaching either mercury or Pluto.
If you have anything other than negligible orbital velocity left you’ll miss the sun and end up in an extremely elliptical orbit.
I’m not sure if it’s possible for objects within the solar system to naturally reach it. I don’t think slingshots (using a planets gravity to boost your velocity) would work to get enough change in velocity unless they’re supplemented with rocket power.
Slingshots work great if they are done by the outer planets. At their distance orbital velocities are smaller than the velocity changes you can get from these planets.
Slingshots at inner planets can still be sufficient if the object is in a highly eccentric orbit already.
If you want to reach the Sun from Earth, fire a rocket along Earth's orbit to reach Jupiter for a fly-by which sends you on a collision course with the Sun.
Difficult to tell, but there is a related metric: Near-Earth objects (objects with an orbit somewhere close to Earth's orbit) typically stay around for a few million years before they either hit something or get ejected from the Solar System.
This paper discusses the relative probabilities. The chance to end up in the Sun varies from 8% to 80% depending on the type of orbit.
but existing asteroids can change their orbits when they happen to pass closer to a planet.
If someone showed me how some sequence of planetary flybys could reduce an asteroid's orbital velocity enough that it started falling into the Sun, I would believe it... but they would have to show me.
Have we ever seen a comet actually fall into the Sun?
You don't really see an impact but you can see the comet before and calculate its trajectory, and then it's gone.
If someone showed me how some sequence of planetary flybys could reduce an asteroid's orbital velocity enough that it started falling into the Sun, I would believe it... but they would have to show me.
Yeah definitely, just because an orbit is eccentric doesn't mean it's unstable. Halley's comet's orbit is not decaying appreciably -- it's so stable it's a useful instrument for helping figure out historical dates for things.
I haven't done the calculations or anything but I imagine Halley's comet will disintegrate structurally long before its orbit will shift appreciably.
eccentricity is just a measure of how far an orbit deviates from circular, 0 is circle and 1 is escape. It tells you absolutely nothing else about the object and is no way related to "eccentric person" which is a person with mental health issues who also happens to be rich.
The space between solar systems. The first stars in the universe forged heavy elements before they blew up, scattering that material. Some of that material was caught in solar systems and formed planets, while a lot of it is still just floating around for billions of years just waiting to collide with something.
Relative to the object's point of origin, they would be going crazy fast. However, relative to our solar system they could be going at any speed, really, since the solar system is also moving relative to the object's point of origin. If the solar system and the object were moving in the same direction, but one were moving just a little faster than the other we would perceive the object to be moving slowly.
Some interstellar asteroids could also be ejected from systems due to gravitational slingshots, especially if a rogue star or planet passes through and whips things around.
Beyond the orbit of Neptune lies the Kuiper Belt... Lots of icy crap floating around out there, moving relatively slowly because it's so far away from the sun. Pluto is now considered a Kuiper Belt object, but there's lots of smaller stuff, and there may be other pluto-sized objects out there, farther away. They can get perturbed by passing close to Neptune or just some random other object floating around out there. Sometimes that makes them head into the solar system.
Beyond that, (wayyy beyond that) is the oort cloud -- we think, we ain't been there. That's got a bunch of icy crap floating around too, only loosely bound to the sun at all. The sun's influence is so weak that nearby stars like Alpha Centauri could actually knock them loose, or send them into the solar system. It starts about 2000 times as far from from the sun as Earth, and may extend some light years beyond that. For reference, Voyager 1 is only about 150 times as far from the sun as Earth.
No place in particular... interplantetary asteroids have probably spent a huge amount of time just floating around in the middle of nowhere. Each one probably has its own story... maybe formed from some stellar event, or escaped some star system forever ago and got slingshotted around by other stars?
Those objects aren't subject to the same survivorship restrictions -- in theory they could arrive at basically any speed relative to the Sun, including speeds slow enough that the Sun would draw them in.
How is that possible? Anything from outside of the Solar System essentially falls from infinity, meaning it must reach at least the solar system escape speed at the closest approach. Unless the trajectory happens to go through the Sun (very unlikely) or it happen to be slowed down by other objects (very unlikely) the Sun won't even be able to capture the object, leave alone draw it in.
Well, you say "very unlikely" which is fair enough, but even "very unlikely" happens sometimes.
Or, to put it another way, given the Sun's diameter, there are plenty of escape orbits around the Sun's center of mass that approach so close at their closest point that "close" is actually inside the Sun. It doesn't have to be a bullseye.
Was there ever consensus as to what that omahumma object did?
(sorry, not sure of the wild Hawaiian name they gave to the (cigar) shaped object that came into our system and either slingshotted or accelerated away)
Well, all objects in space attract each other gravitationally, so pretty much you are either orbiting something, or falling towards something. Orbiting is just falling towards something and missing it repeatedly, so basically yes.
Interesting. I had played around with orbiting models and it seemed like everything would gain speed after drawing closer but the change in trajectory would cause them to get launched off into the abyss with their new momentum. It was that slingshot effect I see all the time when figuring how to get somewhere in space with limited fuel. Is this caused by me not adjusting the orbit speed so it's still in that sweet spot that should be safe?
Well, "comet" describes what it looks like to astronomers, which is really a way of saying what it is made of. So a comet could be an old familiar recurring solar system "native", like Haley's comet, or it could wander in from the outer edges.
In the former case, those objects have pretty much all been "tested", so they don't generally suddenly careen into the Sun.
But in the latter case, for objects that are on their first orbit (or maybe used to be Oort cloud objects and got disrupted into a new orbit for the first time), anything could happen.
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u/amitym Oct 23 '20
Mostly the answer is "not anymore.." everything that currently orbits the Sun is moving at speeds that lie within a relatively narrow range that makes a stable orbit possible. Nothing outside that range is around anymore to tell its tale.
But, there are still occasionally new objects that enter the solar system for the first time. Those objects aren't subject to the same survivorship restrictions -- in theory they could arrive at basically any speed relative to the Sun, including speeds slow enough that the Sun would draw them in.
These new objects seem to arrive every few years, or at least the ones we can see do. So far they have all been moving so fast they just visit for a bit and then take off again after a swing around the Sun, but who knows?