Questions tagged [planet]
Questions on astronomical objects orbiting a star massive enough to be rounded, not massive enough to cause fusion, and which have cleared its orbit of planetesimals.
763
questions
15
votes
2
answers
3k
views
Why is it impossible to infer the surface temperature of Venus by spectroscopy observation from earth?
It is well known that the surface temperature of the sun is determined by fitting the sunlight with the black-body spectrum.
Why is this inappropriate for Venus?
I have the question because of the ...
- 289
1
vote
1
answer
107
views
Planets Named After Roman Gods, Except Earth
I’ve looked this up, but not necessarily sure the internet has the right answer. Why are the planets in our solar system named after Roman gods, except Earth, and why is only one of the nine planets ...
- 4,392
3
votes
3
answers
992
views
Celestial "orbits"
I heard that we're losing our moon, its slipping away from us in such tiny imperceptible steps that we don't notice any significant change even over kiloyears.
The same must apply to planets, inching ...
- 6,721
8
votes
1
answer
3k
views
Why did the dust between the planets disappear during the birth of the solar system?
I'm catching up on my childhood mistakes. One of them was the "nuclear flash", the enormous explosion when the sun ignited. Apparently, this did not happen as the ignition of the sun was a ...
- 146k
9
votes
1
answer
134
views
How is a Planet's Moment of Inertia Measured Remotely?
In the July 2023 issue of Sky & Telescope there is an article titled Sights Set on Uranus. In that article the following statement is made:
Since the 1930's we've suspected that Uranus and ...
- 2,319
7
votes
1
answer
539
views
Is there a formula for calculating surface temperature of a rocky world based on atmosphere and solar input?
For example, a thicker atmosphere would probably lead to less temperature variation . . . I assume that much is obvious. And, greenhouse gases trap heat.
But when posed with a question like "...
- 9,757
3
votes
2
answers
197
views
Everything always looks the same
By now I have used 3 different telescopes and a pair of binoculars and no matter what I try to look at at night, whether it be stars, planets, drones, the moon or whatever, everything looks the same. ...
7
votes
4
answers
669
views
What was the definition of a planet before August 24, 2006?
In 2006, the IAU produced a definition of what it is to be a planet. This definition famously excludes Pluto, to the disarray of this small body's fans.
Before this decision, what was the definition ...
- 200
11
votes
2
answers
6k
views
Why does the planet Saturn have numerous (62) moons compared to the rest of the planets in the Solar System?
Saturn is a gas giant like Jupiter. It has everything from
tiny moonlets less than 1 kilometer across to the enormous Titan, which is larger than the planet Mercury. Saturn has 62 moons with ...
8
votes
1
answer
4k
views
How much of the surface of other planets is lit by the sun?
Since the sun is much larger than the earth, it should ideally light up a considerable portion of the earth rather than only half of it.
However the sun lighting only half of the earth can be ...
- 2,319
0
votes
1
answer
85
views
For what period of time can planets be viewed from the North Pole as just being there?
I would like details on observations (since North Pole is not possible, approximately around the North Pole) which tell us for how long are planets visible from the North Pole?
I understand that ...
- 116k
1
vote
2
answers
116
views
Potentials of space mining [closed]
I'm conducting research on the potential benefits of space mining on asteroids, like 16 Psyche. I'm hoping that those who are more knowledgeable than me can help with the following questions:
Are ...
- 317
5
votes
1
answer
521
views
Difference in results between JPL Horizons and cspice (rust-spice)
I am calculating the apparent planetary position of planets using the cspice library (I am specifically using rust-spice, which is a wrapper of cspice in Rust).
when I calculate the same values in the ...
- 289
4
votes
2
answers
881
views
Would Venus have any significant effects on Earth if its orbit were entirely within the habitable zone?
If Venus was entirely inside the habitable zone, or life zone, would its proximity to the Earth provoke any remarkable changes to the Earth?
4
votes
2
answers
325
views
What celestial body (inside the solar system) has the highest flattening ratio?
As a planet, Saturn has the highest flattening(ellipticity) which is 0.09796. So, it makes Saturn with the largest equatorial bulge as a planet and as such Saturn is the flattest planet.
However, I ...
- 31.3k
0
votes
1
answer
196
views
Why don't scientists believe Earth's surface water came up from the mantle?
I read, periodically, that there is more water trapped in the mantle than there is in the oceans - possibly a lot more.
If so, why don't any geologists believe that Earth's surface and near-surface ...
- 310
14
votes
5
answers
4k
views
Why can't a half-illuminated planet support life at all?
Here is my own translation of the Polish version of the Drake equation article in Wikipedia:
(...) They must provide the right amount of heat. The smaller the star, the less heat it gives off and the ...
- 111
1
vote
1
answer
53
views
Is the magnetic permeability (mu_0) necessary in the expression for planetary magnetic field?
To numerically analyse the Lorentz effect due to the magnetic field, say, radial component on a charge particles which of the expression would be correct, $\{ B_r = \frac{2R}{r^3} g_1^0 \cos(\theta) \}...
- 146k
2
votes
0
answers
98
views
3
votes
1
answer
176
views
When did Venus get as hot as it is now?
My previous question turned out to not ask the question I thought I was asking.
I have read that Venus began its heating-up around 700-750 million years ago.
When did the Venusian atmosphere get ...
- 1,208
4
votes
1
answer
94
views
When did Venus reach approximate radiation equilibrium?
I have read that Venus is roughly at radiation equilibrium - that is, heat out is approximately equal to heat in. I have also read that Venus began its heating-up around 700-750 million years ago.
My ...
- 9,757
1
vote
1
answer
97
views
Does the Sun have different unique orbits around barycenters?
After reading this question and seeing its image I thought about this question I'm going to publish.
Does the Sun have different unique orbits around the barycenter for its multiple planets?
If yes, ...
- 2,023
5
votes
3
answers
2k
views
Moons with synchronous rotation in our solar system
Are all moons in our solar system rotating synchronously around their planet? If not, what are the criteria that some do and some don't?
Many thanks for any insights!
- 1,073
5
votes
1
answer
3k
views
When did astronomy first discover that the stars are bigger than the moon?
We take it for granted these days that the stars are bigger than the planets and the moons. But when you look at the sky, it does not appear this way.
The Moon looks bigger and brighter than the stars....
- 146k
11
votes
3
answers
1k
views
What is the long term fate of the gas giants?
If I'm not mistaken, it is believed that the reason for such turbulent weather on the 4 outer gas giant planets is that the internal pressure is so great that it is generating heat, which is causing ...
- 146k
4
votes
5
answers
319
views
If an orbit is shifting due to orbital precession, is it still a Keplerian orbit?
I was thinking about orbits a few days ago, and realized that orbits shift/precess naturally. Given that a two-body problem with a star and a planet, if the planet has an eccentric orbit that ...
- 2,867
7
votes
2
answers
238
views
How common for all 7 planets to be above the horizon?
I was planning for the Solar Eclipse in April 8th 2024 and noticed that at the time of totality at my location in Western NY, all 7 planets will be above the horizon. Earlier in the day it's all of ...
- 3,318
-5
votes
2
answers
126
views
Is Proxima Centauri a Planet?
Proxima Centauri meets all the requirements for Planet status, although it is a star, can an object be a star and a planet at the same time? normally, the answer should be no, but this is the problem ...
- 11
4
votes
1
answer
179
views
Can rings last around planets indefinitely?
Apparently, Saturn is losing its rings (https://weather.com/en-IN/india/space/news/2023-05-04-saturn-is-losing-its-rings-webb-may-tell-us-how-long-they-have-left) However, is there any way or ...
- 3,318
1
vote
4
answers
271
views
Tilting cycle vs orbital cycle of earth
Common sense tells us a year is conveniently divided exactly into four seasons. I'm wondering whether that means the earth's tilting cycle is equal to its orbital cycle. If so, there must be a reason. ...
- 18.2k
14
votes
9
answers
3k
views
Is Pluto still a dwarf planet?
Recent news seem to suggest that astronomers are arguing about whether Pluto should become a planet again.
However, I cannot find an official source for this. Is this actually true?
- 959
-1
votes
2
answers
317
views
What is the most common method that a scientist uses to study the cyclones in the universe?
Cyclones have been observed throughout the universe as seen in the following examples:
Jupiter's Great Red Spot is perhaps the most well-known cyclone in our solar system. It is a giant storm that ...
-3
votes
1
answer
162
views
Planets revolving counter clockwise around the Sun
Planets revolving around the Sun
Hypothetical case:
What could have been or no impact if the planets viz Earth, Jupiter, Saturn, Mercury, Venus, Mars, Pluto, Uranus, Neptune in different orbits ...
- 1,241
-1
votes
1
answer
510
views
If I know apparent planetary positions how do I calculate the date?
I have planetary position in retrograde how do I calculate the date?
For eg, I know Mars was in retrograde in Scorpion (Sidereal 210 to 240 deg), how do I calculate the date and year of this?
As of ...
3
votes
1
answer
191
views
Is there any "scale" for measuring salinity of extraterrestrial water?
Continuation of Is the water underneath Europa's ice cap potable?
The referenced question discussed if water from Europa's ice caps is potable or not and from the answers, it was gathered that ...
- 2,169
8
votes
1
answer
401
views
Why do the Sun and gas planets rotate faster at equator than at poles?
From this site, it states that:
The Sun spins faster at its equator than at its poles.
I have also read somewhere that the gas giants (gaseous planets like Jupiter, Saturn, Uranus, and Neptune) also ...
3
votes
2
answers
1k
views
Exo Planets and Planets difference?
After hearing that it has been confirmed that we found seven similar exoplanets like earth. I thought exoplanets were dead stars. After doing a little bit of research I found out that exoplanets are ...
9
votes
4
answers
4k
views
Planets looks like normal stars when I see them using telescope
I've been trying to see planets using my 114 mm (aperture) f=900 mm telescope. For the moon, I got very good quality pictures, but when I try to see planets they just appear to be as if I'm looking at ...
3
votes
1
answer
146
views
How is a planet (or star's) radius defined?
The radius of a rocky planet like earth is fairly easy to define based on the fact that the ocean's surface is fairly smooth, and it is a natural point to measure. Other planets like Mars, the surface ...
- 31.3k
1
vote
3
answers
143
views
Are there such circumbinary planet configurations that two suns move towards each other by the sky?
Is it possible that suns move towards each other (not necessarily in opposite directions)? Such a configuration would cause interesting dusk and midday light cycles, in my opinion.
Basically the ...
- 4,780
2
votes
2
answers
1k
views
On a log-log plot of surface gravity to planet mass, what is the meaning of the y-intercept?
I am playing around with data from exoplanets.org, and am interested in the plot of surface gravity to planet mass. I reproduced this plot:
after downloading their data and performed a non-linear ...
- 146k
-2
votes
1
answer
61
views
Can a star with a stellar mass of 1.176 with a similar composition to the Sun have a planet with these characteristics?
Imagine a solar system similar to ours that has a star with a similar composition to the Sun and a stellar mass of 1.176 and an Earthlike planet with about 1.18 times the mass of Earth in its ...
- 116k
0
votes
1
answer
74
views
What stellar conditions and orbital distance are needed to produce a year length of 515 Earth days and 9 Earth hours on an Earthlike planet?
A planet has a year length of 515 Earth days and 9 Earth hours. It is the same size and has the same climate as Earth. What stellar conditions would be needed to produce this and what orbital distance ...
- 13.2k
2
votes
3
answers
400
views
How do rocky planet break up? Would they fragment into "a gazillion" rocky pieces pieces, or crack open like an egg?
I remember seeing Star Wars, where Darth Vader shoots a superb laser (Death Star) to obliterate a populated planet, Alderaan (how inhumane).
The problem is, the planet cracked into a gazillion rocky ...
- 132
4
votes
2
answers
4k
views
Does the earth spiral around the sun's movement/motion path?
I have watched the following video (How Earth Moves by Vsauce) regarding how earth moves:
I have some questions:
Does the earth spiral around the sun's path as it is ...
- 4,392
3
votes
2
answers
579
views
What is the planet relative to earth that shows the greatest change in apparent brightness?
What is the planet relative to earth that shows the greatest change in apparent brightness?
I think the answer is Mars, and a quick google search reveals it is Mars.
I have my reasoning here, but I ...
4
votes
1
answer
1k
views
Can one or more moons orbit around a double planet system?
Given a double planet system where the two bodies are of similar mass;
Can a moon orbit one or both planets in a stable orbit?
How about an artificial satellite?
- 14.4k
3
votes
1
answer
92
views
Why do the radii of the outer planets' epicycles have to be aligned with the earth-sun radius in the Ptolemaic model?
I read that in the Ptolemaic model (or the geocentric system), for the retrogade motion to occur at opposition, the radii of the outer planets' epicycles have to be aligned with the earth-sun radius. ...
- 17.7k
1
vote
3
answers
741
views
why does earth have speed?
I understand that Earth has a quite big speed such as it ends up around the orbit. The sun can't really attract it till the end due to Earth's speed and earth really can't escape due to gravity, hence,...
- 221
2
votes
1
answer
834
views
Is there a relation with the noun planet and to be in a plane?
This morning I was in the shower and it struck me that the word planet might be related to the fact that the PLANEts orbit the sun in a PLANE. Did this naming somewhat happen by accident or was it ...
