Most Popular
1500 questions
15
votes
2 answers
Are stars attracted to one another by their magnetic fields?
What effect do the magnetic fields of stars have on one another:do they tend to repel or attract one another?
user50918
15
votes
3 answers
What is the Neupert Effect?
This effect is frequently discussed in the context of solar time series. In particular, it a relationship between soft x-ray (thermal emission) and hard x-ray (nonthermal emission) from the Sun.
ehsteve
- 1,164
- 8
- 14
15
votes
1 answer
What are some theories that explain the 11 year solar cycle?
The Sun exhibits a periodic cycle for solar activity as manifested by solar activity (e.g. sunspots, solar flares). This activity is related to magnetic fields which emerge from the interior of the Sun. The magnetic fields are created by the solar…
ehsteve
- 1,164
- 8
- 14
15
votes
3 answers
Is there more dark matter than we previously thought?
With the recent Nature publication showing that M dwarfs did not form in prior epochs as frequently as we had thought, what implications does this have on galaxy mass estimates and, by extension, the amount of dark matter necessary for galaxies to…
Justin T
- 3,404
- 10
- 32
15
votes
9 answers
How do we know we're not getting bigger?
Alright so I've been thinking a lot about how the universe expands and I've always wondered if we're getting bigger as well. Since everything would be getting larger at an equal rate (tools of measurements, atoms), would it even be possible to…
Landon
- 169
- 1
- 3
15
votes
6 answers
What's the issue with Olbers' paradox?
I'm not quite grasping the reasoning behind Olbers' Paradox, or why an eternal, non-expanding and spatially infinite universe would be incompatible with a dark sky. For simplicity, let's suppose that all the stellar matter in the universe is…
Alex Popescu
- 153
- 1
- 5
15
votes
2 answers
Does the Inverse Square Law mean that the apparent diameter of an object of same mass has the same gravitational effect?
Someone else asked about various planets located at the orbital range of the Moon. It made me wonder if an object with the same density as the Moon, at a distance which would present the same angular diameter of the Moon seen from the Earth, would…
JohnHunt
- 816
- 5
- 10
15
votes
2 answers
How could Mars' atmosphere be shed by solar winds, when Venus has a thick atmosphere despite no magnetic field?
Our current understanding of how Mars lost its atmosphere is because it lost it magnetic field, due to a barrage of reasons, such as core cooling due to low volume and cooling off quickly. This resulted in solar winds stripping away its atmosphere,…
Alastor
- 2,639
- 1
- 9
- 35
15
votes
3 answers
What happens when the quasar remnants reach Earth in 3 million years?
According to this article (A quasar Milky Way six million years ago?), during:
(during) a quasar stage in its evolution (6 million years ago) ... the Milky Way’s central black hole swallowed a huge amount of gas, creating a shock wave that has now…
RonJohn
- 409
- 3
- 10
15
votes
7 answers
How did the Milky Way quasar not disrupt life on Earth?
According to most sources of information I have found (A Quora answer and books), when galaxies become quasars, they destroy all life in their host galaxy, as they output so much radiation that they can disintegrate DNA and do lots of bad stuff,…
Alastor
- 2,639
- 1
- 9
- 35
15
votes
0 answers
What 1° x 1° region is the optically darkest patch in the sky?
What 1° x 1° region of the night sky has the lowest flux of light?
(considering the typical visual/luminance filter range, approximations using other filters/bands are acceptable, but should be in the optical)
2080
- 1,888
- 7
- 22
15
votes
2 answers
What determines the speed of a star's solar wind?
I'm wondering if different stars produce wind at different speeds, and if so, what factors determine that speed.
Per this answer, our star produces wind with a speed between ~250–820 km/s. It seems safe to assume that the wind speed for each star is…
Tom
- 251
- 1
- 5
15
votes
1 answer
Has a magnetic field flip of a distant star ever been measured?
The magnetic field of the Sun flips during each solar cycle, with the flip occurring when sunspot cycle is near its maximum. Levels of solar radiation and ejection of solar material, the number and size of sunspots, solar flares, and coronal loops…
2080
- 1,888
- 7
- 22
15
votes
6 answers
How is this picture of the moon possible?
I need help understanding this images I personally took. If the phases of the moon are determined by the position of the earth, moon & sun. Then how is the moon a crescent while it is rising in the east with the sun & still a crescent while setting…
Cody Page
- 151
- 1
- 3
15
votes
2 answers
Is it Possible for Planetary Bodies To Exist In Close Proximity Without Adverse Effects?
There are several sci-fi movies where planetary bodies are shown in the sky in order to indicate that the characters are on an alien planet. A good example is in Predators (2010):
Is it actually possible for such planetary bodies to exist so close…
KalenGi
- 253
- 1
- 5