Questions tagged [rotation]

Questions regarding the action of or an object rotating along an axis.

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20
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3answers
1k views

Why does a planet rotate and revolve?

Why do planets rotate and revolve in the universe?
10
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2answers
1k views

Cancelling out earth rotation speed, Altazimuth mount

I have a Dobsonian telescope. It is using Altazimuth mount. Basic idea of using it is to target the object by moving telescope vertical axis perpendicular to the ground, and an elevation axis that ...
30
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4answers
10k views

Why do (most of) the planets rotate counterclockwise, i.e. the same way the Sun does?

Referring to the mechanisms explaining the solar system formation and to the initial rotation of the gaseous cloud that collapsed, I understand easily why the planets orbit the Sun the same way this ...
29
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2answers
2k views

What is the current accepted theory as to why Venus has a slow retrograde rotation?

According to this NASA overview, the planet Venus is unique (amongst the major planets), Venus has a slow retrograde axial rotation, taking 243 Earth days to make one rotation (which is longer than ...
3
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3answers
862 views

Inverse of the sunrise equation - finding locations with a given sunrise time on a given day

I'm working on a project for fun where I represent some sleep data geographically. For a given day, I have a date, a time for falling asleep that night, and a time for waking up the next day. The idea ...
22
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1answer
1k views

What is the accepted theory as to why Uranus' axis is tilted so severely?

The planet Uranus is another solar system anomaly, where according to the NASA profile has an axial tilt of 97.8 degrees, also considered to be retrograde. This NASA summary "Uranus" suggests the ...
20
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1answer
838 views

Is Earth's orbital eccentricity enough to cause even minor seasons, without axial tilt?

I was reading the answers to this question about an exoplanet having seasons without axial tilt, and several responders mention that orbital eccentricity could cause a similar effect, but that the ...
10
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1answer
14k views

How would Earth's climate differ if it's axis were tilted around 90 degrees like Uranus? [closed]

As the title states, what would the effect on Earth's climate be if it's axis were tilted approximately 90 degrees like Uranus? I'm specifically wondering about the effects on seasons, temperature, ...
7
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4answers
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Are there any known planets whose axis is oriented such that one pole always faces its star?

Earth rotates around the sun and around its axis (A North, South axis) giving us days, nights and seasons. Are there any known planets that rotate with an axis pointing toward its sun so that one ...
6
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2answers
506 views

Could the merger of two rotating black holes create another that breaks the rotational speed limit?

The black hole GRS 1915+105 was observed to be spinning at near the theoretical maximum spin rate. Assuming you had two such black holes spinning clockwise, and also orbiting each other clockwise, ...
3
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1answer
510 views

What makes the Earth infinitely rotating around its axis

I was reading two sites before I posted the question here. One site says something like that the collisions in Universe eventually set the planets rotating, another site says that our planet is formed ...
6
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1answer
174 views

Are there collected data about the direction of rotation of black holes and the direction of the magnetic field?

Is there a relation between the direction of rotation of black holes or neutron stars and the magnetic dipole moment of BH or neutron stars? BTW, are there different directions of this two parameters ...
3
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2answers
1k views

If the earth stopped rotating, would we really fly inertially at 1000mph? [closed]

I heard this on Prof. Neil Tyson's StarTalk podcast (this episode) and had a question about it. In a Q&A session, a listener had asked what would happen if Superman really did stop the earth from ...
3
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1answer
119 views

Uranus' axis of rotation-when discovered?

Who discovered it, and how was that accomplished. I had assumed it was known before Voyager 2 arrived at the planet since it isn't mentioned in JPL voyager 2 Uranus Approach
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6answers
6k views

Does the Sun rotate?

The planets rotate as an after effect of their creation, the dust clouds that compressed span as they did so and the inertia has kept it rotating ever since. It's fairly easy to prove that planetary ...
20
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2answers
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How did Mars come to have a 24 hour 39 minute day?

Mercury rotates three times for every two revolutions around the Sun, apparently due to a gravitational resonance with the Sun.Venus takes about 225 days to rotate, and rotates in the opposite ...
10
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4answers
7k views

Do solstices and equinoxes shift over time?

Right now, I think the winter solstice is around December 21. Has it always been around this date constantly? Since the earth's axis's 23.45° tilt will be on the exact opposite side in 13000 years (...
2
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0answers
131 views

Modeling planet rotations (time of day, obliqueness, etc.)

I created this solar system model using POV-Ray: by following these instructions: https://ssd.jpl.nasa.gov/txt/aprx_pos_planets.pdf The next thing I want to do is orient/rotate each globe correctly ...
14
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4answers
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Would an exoplanet without axial tilt have no seasons?

Would an Earth analog exoplanet which rotates around a solar analog, but without axial tilt, have no seasons? Would it be similar to how Los Angeles does not have very noticeable seasons compared to ...
11
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3answers
6k views

Why is twilight longer in summer than winter and shortest at the equinox

I recently decided to set my alarm clock to wake me up when it is "dark" out. In the end, I decided to set my clock to the earliest time that nautical sunrise is in my state (Illinois) and stick with ...
10
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2answers
13k views

If Earth didn't rotate, would we feel heavier? [closed]

Suppose the Earth's rotation slowed for some reason. Would the lack of centrifugal force cause us to feel heavier than normal? Likewise, if Earth's rotation increased, would we feel lighter as ...
5
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2answers
712 views

Why most planets don't spin retrograde? [duplicate]

Edit: just found duplicate Since orbital velocity is greater on small orbits, and smaller on large orbits, why don't planets spin retrograde around their own axis? One portion of planet's mass is ...
4
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1answer
119 views

What is a black hole's “shadow” and the best angle to view it to measure the spin?

This excellent answer mentions several ways to try to observationally measure the spin of a rotating black hole. The third one is intriguing, but I don't understand how this works: The spin of a ...
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1answer
4k views

What causes objects to become tidally locked?

I'm trying to write a gravity simulation (suns planets etc), and was hoping tidal locking could be one feature demonstrated. Using a simple equation for gravity has produced some interesting results, ...
2
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2answers
658 views

What is the axial tilt of a planet measured relative to?

I am very much a beginner on the astronomy front but I understand about planets having different axial tilts, hence why Venus turns the opposite direction from the Earth and Uranus turns sideways. ...
2
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1answer
70 views

Rendering asteroid orientation as seen from Earth

I am writing a program to render an asteroid as seen from various parts of the solar system. My goal is to roughly reproduce the image of Cacus according to information on its DAMIT detail page. ...
4
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2answers
688 views

Motion of rogue planets

Two Questions: 1) Are rogue planets in motion, i.e. are they just wandering freely in space or stationary? 1) Do rogue planets have defined path or a one which can be anticipated? I understand that ...
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2answers
3k views

Why are tides biggest during the equinoxes?

I've read that during the equinoxes, tides are at their maximum. Shouldn't this only apply to latitudes near the equator? I mean, when the solar declination is near to 0º and we have a full or new ...