Questions tagged [speed]

Questions regarding an object's movement, or its distance traveled relative to the time taken.

Filter by
Sorted by
Tagged with
1 vote
2 answers
113 views

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 ...
alphaaquilae's user avatar
6 votes
2 answers
242 views

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 ...
user209974's user avatar
4 votes
2 answers
5k views

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 ...
Ed_Gravy's user avatar
  • 317
2 votes
0 answers
89 views

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 ...
w94n9's user avatar
  • 51
0 votes
1 answer
193 views

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 ...
James Long's user avatar
3 votes
0 answers
69 views

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 ...
Dimitris's user avatar
4 votes
1 answer
145 views

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 ...
the gods from engineering's user avatar
2 votes
1 answer
93 views

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?
bmp's user avatar
  • 23
14 votes
3 answers
7k views

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 ...
Rob Dirnens's user avatar
1 vote
1 answer
310 views

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 ...
Iks Deh's user avatar
  • 11
1 vote
2 answers
188 views

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 ...
Wahyu Kristianto's user avatar
0 votes
2 answers
141 views

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 ...
500 - Internal Server Error's user avatar
0 votes
1 answer
99 views

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?
TryingMyBest's user avatar
0 votes
1 answer
141 views

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?
INHYUK PARK's user avatar
-4 votes
1 answer
126 views

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.
Tardy's user avatar
  • 245
1 vote
1 answer
154 views

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 ...
RonS's user avatar
  • 577
2 votes
2 answers
460 views

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 ...
18.99's user avatar
  • 21
0 votes
1 answer
181 views

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 ...
user avatar
-1 votes
1 answer
612 views

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 ...
Stephan Møller's user avatar
1 vote
1 answer
510 views

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 ...
Malekai's user avatar
  • 165
3 votes
0 answers
61 views

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?
user avatar
43 votes
5 answers
11k views

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 ...
Emir's user avatar
  • 431
1 vote
1 answer
169 views

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 ...
user30007's user avatar
  • 1,226
3 votes
1 answer
70 views

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 ...
chron0's user avatar
  • 31
11 votes
4 answers
10k views

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 ...
Rabadash8820's user avatar
46 votes
2 answers
6k views

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 ...
Patrick Trentin's user avatar
6 votes
1 answer
372 views

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 ...
uhoh's user avatar
  • 30.8k
9 votes
2 answers
6k views

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 ...
ThePiachu's user avatar
  • 259
4 votes
3 answers
3k views

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 ...
enochroot's user avatar
0 votes
1 answer
108 views

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 ...
jidh's user avatar
  • 145
3 votes
1 answer
202 views

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?
J. Doe's user avatar
  • 283
1 vote
1 answer
257 views

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 ...
Max0815's user avatar
  • 1,862
1 vote
0 answers
23 views

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 ...
PL_Pathum's user avatar
  • 133
0 votes
2 answers
2k views

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 ...
Muze's user avatar
  • 1
3 votes
2 answers
107 views

Superluminous super nova output

I was reading about how powerful supernova were and found out there are even bigger supernovae also called hyper nova. A large explosion was discovered in 2016 I believe (or was it 2017). I would ...
Logikal's user avatar
  • 245
5 votes
4 answers
2k views

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 >...
John Joe's user avatar
  • 261
28 votes
1 answer
5k views

How did Ole Christensen Romer measure the speed of light?

How did Ole Christensen Rømer, who in 1676, shortly after Galileo's death, was said to have measured the speed of light as 220,000 km/s by timing the orbits of Io around Jupiter? My only guess is ...
Michael Lee's user avatar
0 votes
1 answer
329 views

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 ...
Muze's user avatar
  • 1
3 votes
2 answers
714 views

When would Oumuamua have entered the solar system?

So from what I've read, Oumuamua travels at around 26km/s when in interstellar space. I also remember reading a while back that Voyager was travelling at around <...
user avatar
-1 votes
2 answers
181 views

How did Earth get here before gravitational waves?

If GWs propagate at near the speed of light, how did Earth (and its constituent elements) arrive at its current location billions of years before the GW arrived here (or light from distant stars for ...
iMerchant's user avatar
  • 1,062
6 votes
3 answers
3k views

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 ...
Chris Allen's user avatar
1 vote
2 answers
169 views

Is there any cosmological evidence that neutrinos travel at a speed other than c?

I've been looking into neutrinos. One thing I'm puzzled about is how fast they travel. See the Wikipedia SN1987A article where you can read this: “approximately two to three hours before the visible ...
John Duffield's user avatar
11 votes
2 answers
332 views

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?
Zamicol's user avatar
  • 1,005
4 votes
1 answer
214 views

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 ...
Pablo's user avatar
  • 1,103
2 votes
1 answer
74 views

Speed gaseous planets

Why do gaseous planets spin faster than telluric planets? I've seen thats because of primitive nebula but I didn't understand why? Could someone help me? I would appreciate a lot!
Francisca Sousa's user avatar
2 votes
3 answers
2k views

Are we already moving faster than light?

Okay, so the speed of revolution of earth around sun is 30 km/s[1], speed of revolution of sun around milky way's center is ~200 km/s[2], speed of rotation of milky way is 828,000 km/h[3] i.e. 230000 ...
completely newbie's user avatar
10 votes
2 answers
2k views

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{...
CipherBot's user avatar
  • 1,301
0 votes
2 answers
761 views

The light of which star is next to reach the earth?

I heard that the sky wouldn't be dark at night if the light of every star had already reached the earth. Of which (currently invisible) star will the light reach the earth next and when will that be? ...
Albert Hendriks's user avatar
0 votes
2 answers
159 views

Regarding the age / size of the Universe [duplicate]

I believe the current estimated age of the Universe is around 14 billion years. I just read in another post on here that the diameter of the Universe is around 90 billion light years. This doesn't ...
John's user avatar
  • 11
6 votes
2 answers
288 views

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 ...
Lonnie Best's user avatar