Questions tagged [speed]
Questions regarding an object's movement, or its distance traveled relative to the time taken.
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Determining the speed of meteor
How to determine the velocity of a meteor from two video data?
I want to try to determine the orbit of the meteor, but before that I have to determine the meteor's entry velocity and apparent radiant ...
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Why do we say that gravitational waves travel at the speed of light, when they can escape a black hole and light cannot?
Or rather, does "speed" relate to the same measure? The speed of light is the speed of a photon/an electromagnetic wave in the empty space, but gravitational waves are wave of this very same ...
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Why speed of light is considered to be the fastest?
According to Hubble's law, as things move further and further away from one another, there might come a point when their speed gets faster than the speed of light. So, why is it that the speed of ...
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Space travel relative to solar system's movement through space
Assuming our entire system (stars, planets, etc) is moving through space at around 180,000 mph. Why can't we leave in a direction opposite our system's movement to achieve deepspace flight?
Part two
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Find position of orbiting body along orbit efficiently
I'm coding a game, and a fundamental mechanic is celestial bodies moving in elliptical, Keplerian orbits around a single gravitational point in a planetary system (not our solar system). The bodies ...
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Exact measurement of a light year
What is the exact measurement of a light year? I searched google for the answer in meters and came up with $9.461\cdot 10^{15}$ meters. When I calculated the answer considering $299\,792\,458 \;\text{...
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Is there something close to a consensus on Earth-Sun annual distance increase (speed)?
I've seen estimates varying by an order of magnitude, e.g. (New Scientist)
Having such a precise yardstick allowed Russian dynamicists Gregoriy A. Krasinsky and Victor A. Brumberg to calculate, in ...
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How do we know universe is expanding and not light slowing down? [duplicate]
We tend to take some things for granted, for example the light of speed is constant, but what if it isn't? How can we know that light is not slowing down at great distances for example, or that light ...
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Is the light we see from stars extremely old?
Our nearest star Proxima Centauri is 4.243 light years away from Earth.
Does that mean we are seeing light that is 4.243 years old everyday?
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If all objects move, where do we go?
Yes I know that the sun and planets in the solar system travel fast with an average speed of 448,000 mph.
Are we going to the center of the galaxy? If so, does that mean our galaxy is getting smaller ...
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Will Jupiter's days speed up?
Jupiter has so many moons, and those moons have a gravitational pull on it. Does that mean, that over time, the length of Jupiter's days will get shorter?
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It takes light roughly 8 minutes to travel to Earth from the Sun, but based on which perspective?
The passage of time is relative depending on whether one is the stationary observer or the object/particle traveling at the speed of light (or close to it). I get this, kind of. But, when we talk ...
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Calculate speed of a galaxy with redshift
I was going through some old exercises but I could never figure out who to solve this one
The hydrogen absorption line (656 nm) of the galaxy NGC 77 is shifted by 41 nm into the reddish wavelength ...
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What would change if Venus rotated at a speed and direction similar to Earth?
I am interested in two aspects of this question. Imagine that Venus had a similar rotation speed and the same direction of rotation that we have here on Earth.
What would change for Venus itself? I'm ...
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If interstellar medium was dense plasma and light slowed down, would things appear to move slower far away?
Voyager 2 recently left the solar system and registered an increase in plasma density. If light moved slower in this dense plasma, would it appear like events in other solar systems played out slower ...
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What's the fastest moving object in the universe?
We know that nothing can have proper velocities larger than the speed of light in vacuum. But are there any objects in space that get close to it? Any comets, or other objects thrown by gravity or ...
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Seeming conflict between most distant objects and age of universe (both estimated)
There was a recent article on bbc.com for laypeople like me titled "The mystery of how big our Universe really is", which prompted me to post the following question in their comments section ...
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Traversing a proton within the Planck time
If I could travel a super small distance (proton) in an even smaller time (Planck time), how long would it take me to cross the observable universe?
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Does the Sun's light travel fast enough to have a straight path to Earth?
When we travel through space, we use a curved path following an orbit to reach our destinations.
As far as I'm aware, we could take a more straight line approach but it would require much more deltaV ...
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can i use heliocentric velocity as a rotation speed? [closed]
In the research of the galaxies, does heliocentric velocity involves space's expanding velocity? and can i use heliocentric velocity by galaxy's rotation speed?
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Which star / galaxy is moving away from us the fastest?
I know that we have measured the rate a lot of stars and galaxies move away from us using the doppler shift, and I know that the further a star / galaxy is the faster they accelerate away from us due ...
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Can air/gas be slowed down by friction [closed]
Can wind/air that is moving at average speeds be slowed down by the cause of Friction? Also, Can Air bubbles in water be slowed down because of Friction? Please cite your sources.
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Earth Versus Catastrophic Meteor
How evasive is the Earth to Catastrophic Meteors?
Google says the Earth is approximately 92.96 million miles from the Sun. It also says the suns radius is 432,474 miles.
Therefore, it is 93,392,474 ...
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Faster than light?
From what popular science tells us, if I travel at close to the speed of light, I'd age slower.
So if I travel at 99% of SOL and travel the distance of one light year, for other people one year has ...
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How to find the mass of a planet not knowing the gravitational constant?
So I found this problem, I know the gravity of earth $g_0$, I found the orbital speed of one satellite using this equation $\frac{GM_em_s}{(R_e+h)^2}=m_sa$
($M_e$ is the mass of earth, $m_s$ is the ...
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Is it possible to be 'still' in space?
So I was reading this answer about how galaxies are the fastest moving objects in the universe because space is expanding faster than the speed of light. This got me wondering, would it be possible to ...
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how long a light year on earth will seem [closed]
First of all, sorry if this is not the right StackExchange to ask this question, but i don't know a better place (open to suggestion in case).
So, the question:
Suppose that for some reason, we can ...
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How precise are the observational measurements for the speed of gravity?
General Relativity says that gravity moves at the speed of c. How precise are the measurements?
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Absolute zero speed in space [closed]
I have read multiple posts in here about the concept of an absolute zero speed definition in space. However, I have some arguments FOR absolute zero speed, which I would like to write here, and have ...
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What would happen if you jumped out of a moving spacecraft? [closed]
I've watched a film where one of the characters claimed to have rapidly disembarked a moving spacecraft during a 5g burn (?!) and immediately wondered how he survived.
For example, you're on a ...
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How fast is a comet moving when it crosses Earth's orbit?
Is it about the same as Earth's orbital speed?
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Are photons aged?
If a star is at a distance of one lightyear, how old are its photons when they reach earth (from the photons’ perspective)? If time dilation is near zero at light speed, can we assume that the light ...
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If the distance between galaxies is increasing and the speed of light is constant will the most of the light from the universe ever reach us?
Will the light from other galaxies ever reach us if the universe is expanding?
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How fast does a spacecraft have to be to enter a primordial black hole without being torn apart?
If there really is a primordial black hole beyond the Kuiper belt, we can send a probe to the black hole and into it. But how fast must the probe be in order to enter the black hole without being ...
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Is Earth's Surface "In orbit"?
I'm having trouble understanding relative angular/tangential speeds at increasing altitudes above Earth's surface. In particular, I find this comparison of tangential velocities on Wikipedia very ...
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Does the sun cross other spiral arms in its movement around the galaxy's center?
Today, Ansa.it released an article that states:
[...]. In questo suo peregrinare galattico, il Sole ha attraversato anche
i due bracci della Via Lattea Perseo e Centauro. "Sono zone di alta
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So where are these measurements of galaxies moving faster than light?
https://physics.stackexchange.com/questions/400457/what-does-general-relativity-say-about-the-relative-velocities-of-objects-that-a
"we can actually observe galaxies that are moving away from us at >...
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Have more recent LIGO/VIRGO gravitational wave measurements narrowed down the speed of gravity further?
This answer to How precise are the observational measurements for the speed of gravity? says:
...in 2013 a Chinese group built a model using Earth's tides that helped them narrow it down.
... [T]he ...
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Does Absolute Velocity Exist?
It seems everyone is on the same page about there being no "absolute velocity" due to the fact that everything is relativistic. However, this leaves me confused. This seems to be disconnected with the ...
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how to define the universe itself is expanding greater than than the speed of light?
since we observe galaxies and other steller objects in very tiny tiny scale, and how we can understand that the speed of expansion on universe is higher than the speed of light ?
even using the ...
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Are there known objects rotating at close-to-light speeds?
For example, $0.1c < v < c$? Is this actually possible?
Background: is that true that the black hole in the center of the Milky Way rotates once per 20 minutes?
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Possible to use tachyons to explore black hole?
I read on a Wikipedia article lately that tachyons are theoretical particles which always travel at or above the speed of light. That means that when one passes us, we see two images, a blue shifted ...
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What is the fastest spinning rotation of a Neutron star?
What is the fastest spinning rotation of a Neutron star? I have heard that Neutron stars have a specially fast spinning rotation. What is the fastest?
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What would a black hole merger look like?
Ship 1 is out side the black hole. Ship 2 is nearing a black hole. To ship 1 it would appear that ship 2 would be moving slower to the point it would seem like ship 2 stopped moving the closer to the ...
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How the Galactic objects are moving? [duplicate]
We know that the Galaxies are moving very fast, not only the Galaxies other known and unknown objects in the universe, are moving. But when it was started where is the starting point, and how it move ...
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Why don't we feel the speed of earth moving
When we move our vehicle, we "feel" the speed of it. However, when stationary, we still are moving,but moving by quiet a speed. We know that earth moves with X ...
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Does the milky way have relativistic mass against galaxies which are moving away from it at high speeds?
According to the article cited behind, and to a post here in Astronomy SE , there are galaxies moving away from Milky Way faster than light, even at speeds of 2.3c . According to this article
Can two ...
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Does the edge of the Universe travel faster than the speed of light?
The Universe is expanding faster than the speed of light then does that mean matter at the edge of the universe is also traveling at the speed of light or are ether opposite sides of the universe are ...
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How is it known that Pillars of Creation are destroyed?
We can observe Pillars of Creation with 7000 years delay, but it is destroyed only 6000 years ago. How do we know that? How the information about explosion reached the Earth before light do?
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If an object with mass were to somehow go the speed of light, would it destroy the whole universe? [closed]
Would an object with mass traveling the speed of light destroy the whole universe because it would have infinite energy / mass? According to wikipedia and other sources, it takes infinite energy to ...