Does movement of the earth bring difference in the distortion of fabric of spacetime?

Question

The earth is constantly moving with huge velocity. Doesn't this tremendous velocity bring difference in distortion of spacetime at the opposite ends? I mean the end towards the direction of motion and the end opposite to it?

Edit : Taking the resultant of motion around Sun and galactic center as well as motion towards Andromeda plus ..... , the velocity of earth at a particular direction at particular time reaches hundreds of km/sec. I was curious whether this mean anything to fabric of spacetime.

Answer 1

The distortion of spacetime is what keeps the Earth in orbit around the Sun. The distortion is caused by the mass of the Sun. We call this gravity. The distortion near the Earth is tiny on a scale that runs from $0$ to event horizon of a black hole. We often measure gravitational strength in g's. Another way would be to measure deflection of a light ray.

At the surface of the Sun, the strength is $237$ g. Starlight that skims the surface (during an eclipse so you can see it) has been measured as deflected about $1$ arcsec ($1/3600$ degree) from a straight line.

Gravity at the surface of Earth is $1$ g. Deflection of starlight is correspondingly smaller.

Gravity from the Sun that holds the Earth in orbit is tiny, 0.006 g. The Earth takes 6 months to reverse its direction. It is a slow process, and the gravitational attraction that makes it happen is weak. Deflection of starlight by the Sun at the distance of Earth's orbit would be unmeasurable.

By contrast, gravity near a black hole is strong. Light that passes near a black hole, even outside the event horizon, would be bent into an orbit around the black hole that spirals in. See the Veritasium video How to Understand the Black Hole Image

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There is another effect. When two objects orbit each other, distortions of spacetime radiate away as a wave. When two black holes orbit each other at a close distance, this is huge. The energy radiated away comes from the orbital energy. The black holes get closer and closer and merge into one.

The waves spread out over the universe and eventually reach Earth. They are extremely weak when they arrive. Developing an interferometer sensitive enough to measure them took a decades. But we are now able to do it. See The Absurdity of Detecting Gravitational Waves

The first time gravitational waves were measured, two black holes $1.3$ billion light years away merged. The masses of the black holes were 29 and 36 $m_{sun}$. At the end, the orbital speeds were near the speed of light. The orbited $40$ times per second at a distance of more than $10$ km. Think of gravity strong enough to vibrate $65$ Suns at $40$ Hertz with an amplitude of $10$'s of km.

The same thing happens as the Earth orbits the Sun. But of course the effect is much much weaker. It is a truly tiny effect. The gravitational pull of the Sun that keeps the Earth in orbit is $6 \cdot 10^{-4}$ g, Earth's orbital speed is $10^{-4}$ c, $m_{Earth} = 3\cdot10^{-6} m_{Sun}$, and the orbital period is $3 \cdot 10^7$ sec. Each of these numbers is at least a million times smaller than for the black holes.

The gravitational energy radiated away by the Earth's rotation around the Sun is $8$ Watts. The gravitational waves generated by this are undetectable, even with the extremely sensitive instruments we now have. It will take far longer than the age of the universe for this energy loss to make a detectable change to the orbit of the earth.

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Edit - Bow waves

See Journey of a Gravitational Wave This simulation from MIT shows the shape of the gravitational waves.

Even though the simulation doesn't show much detail right next to the black hole, it is save to say there are no bow waves.

A bow wave gets its name from the water that piles up in front of the bow of a ship. As the ship moves, it pushes water out of the way. The water piles up as it is pushed. This is the bow wave.

Something similar happens to planets in the solar system. The Sun pushes out a solar wind, a stream of particles at high velocity. Not very many particles. Space is a good vacuum, but not a perfect vacuum. When these particles encounter the magnetic field of a planet, they are deflected around the planet. This is important - it protects the Earth and keeps its atmosphere from slowly being stripped away. As the solar wind is deflected, it piles up into a bow wave. You can see images in foolishmuse's answer.

But this seems to be different from what you are asking and also different from how matter acts around a black hole.

First, if there is matter around a black hole, it forms an accretion disk. In falling matter is ripped apart as it gets close, simply because one side is closer to the black hole than the other, and gravity gets very strong very quickly as you get close.

Matter is never perfectly aimed at the black hole, so it winds up orbiting around the black hole. In the strong gravity, orbital speeds are near the speed of light. Far faster than speeds from say moving toward the Andromeda galaxy. It winds up in a disk, sort of like the solar system, but made out of hot gas and plasma. So no bow wave from the matter around the black hole, if any.

But you were asking about a bow wave from the fabric of spacetime. Spacetime is often misdescribed. It is not a fabric. It is not a sheet that is distorted by a massive object into a bowl shape. These description are intended to explain particular points about gravity, but they often cause more confusion than they solve.

Spacetime is vacuum. Nothing is there, unless you want to consider virtual particles that pop into and out of existence everywhere all the time. (Another misdescription with its own confusions.) Spacetime is the background that allows you to measure distance and time between two events.

Mass causes distortions in spacetime. Suppose you are in a circular orbit around the Earth. You can measure the distance you travel in an orbit. You could also measure the distance through the Earth from one side of the orbit to the other. The mass of the Earth distorts distances and times very slightly. (Gravity is very weak near the Earth.) The distance across is slightly longer than you would expect from the distance around. Likewise, time runs slightly slower on the surface of the Earth than it does in orbit. See Why can't I do this to get infinite energy?

The effect is the same around a black hole, but much stronger.

When two black holes orbit each other, the motion creates moving distortions. These are just moving regions of changed distance and time interval. They are not waves in matter at all.

Nothing piles up in front of the black holes, particularly not spacetime.

On the other hand, foolishmuse references a speculative theory that says relativistic moving objects do generate a bow wave in front of themselves. If true, this would be a very small effect, because the Earth is not relativistic with respect the Andromeda galaxy.

Answer 2

Velocity is only relative. So it is not moving relative to itself. Therefore, in the Earth’s frame the Earth has the standard non-moving gravitational field.

In another frame, we can simply transform the field in the resting frame to the moving frame to obtain the field in the moving frame. The distortion of spacetime is a tensor and is the same in all frames (its components change, but the underlying geometrical object is the same).

Answer 3

Linear motion does not have any effect on spacetime -- it cannot, because the laws of physics are independent of speed (e.g. $F = ma$ only depends on the change of speed, not on the speed itself). Since speed is relative, any "law" that depended on speed would not be universal. So no, the Earth's speed through space does not affect spacetime.

Earth's rotation does have a small effect on spacetime, because rotation is not relative (there's an absolute sense in which rotation can be detected). This effect is called the Sagnac effect, and is taken into account in the Global Positioning System (GPS).

There is a sense in which Earth's (relative) speed can produce relativistic effects. The Earth's speed relative to itself is 0. Relative to the center of the galaxy, or to the cosmic microwave background, it is higher -- but still nowhere near the speed of light. However, relative to some cosmic rays the Earth does have relativistic speeds (close to the speed of light). In the frame of reference of those cosmic ray particles the Earth is experiencing length contraction so that e.g. the distance from the ground to the top of the atmosphere is small enough that a short lived particle can traverse it before decaying. Of course relative to us the cosmic rays are the ones moving, and we say that the particles are experiencing time dilation and that's the reason they can reach the ground in their (short) lifetimes. Both explanations are perfectly valid, and neither involves a change in spacetime, just in one's choice of coordinates.

Answer 4

Here is a NASA depiction of the bow wave (shock wave) from Saturn. So yes, a planet does indeed create an asymmetric wave through space. Just remember that you can fit 764 Earths inside Saturn, so the bow wave would be much much smaller.

It is very interesting to note that in the search for dark matter, scientists have found that slower moving galaxies, and more diffuse galaxies, have less dark matter in their region than faster or more compact galaxies. There is a speculative theory that it is in fact the movement of these galaxies through space generating a massive bow wave that in turn generates what should be called dark gravity instead of dark matter, because there is no actual matter involved, only gravity.

Here also is a depiction of the bullet cluster of 40 galaxies, which are moving through space at about 1% of C. The stars (normal matter) are depicted in pink and the dark matter in blue. Do you notice the resemblance to a bow wave? Very interesting.