1
vote
1answer
36 views

What was “space” like before big bang?

I have a simple question which I think about often but have no answer. If The Big Bang is true, than if the whole space was just a point 14 billion years ago, then what was around that point, some ...
2
votes
4answers
121 views

What is spacetime 'made' of?

General relativity is often explained as saying spacetime is curved by gravity, what does this mean? How could we perceive a curve in spacetime when there is no external "straight" reference frame for ...
5
votes
3answers
182 views

Does the Sun impose back it's tidal forces onto the Earth (such as the Earth's to the Moon)?

It is known that each year the Moon is moving away from the Earth due to tidal forces. What about the Earth relative to the Sun?
1
vote
2answers
28 views

How to calculate when the moon is highest in the sky to the earthbound observer?

Like when is the new moon highest in the sky? Or third quarter? How do I know this for any general moon phase? Thanks.
5
votes
1answer
793 views

How many earths fit in the observable universe?

I was pondering our insignificance, when I wondered - how how much smaller is our planet then the (observable) universe? And being as I dont know how to do the math, I'm asking it here. So how many ...
6
votes
3answers
300 views

How does light affect the universe?

When light is emitted by for example a star, that star loses energy - which causes it to reduce its gravity. Then that energy begins a journey for potentially billions of years, until it reaches some ...
3
votes
1answer
84 views

Is there a photo that shows a iron meteor or asteroid in space in raw form having no layers of fusion crust?

A raw iron meteor or asteroid in outer space should be in its raw form having no signs of fusion crust from the friction of atmospheric entry and should therefore show distinctive signs like the ...
0
votes
0answers
18 views

plane of moons orbit, self spin with respect to earth's self spin and orbit around the sun? [on hold]

is there an image of plane of moons orbit, self spin with respect to earth's self spin and orbit around the sun? is that Geodesy related or Astronomy related?
0
votes
1answer
61 views

Is there sufficient evidence to confirm additional Planet in solar system

I have watched this scishow episode where Hank says that astronomers believe there is another planet in our solar system. Link He says that it's because how asteroids and comments are being pushed ...
4
votes
1answer
34 views

Calculating longitude from star culmination

Here is the problem: I need to calculate longitude of observing place. And I know time (in UTC+1) of star culmination (Sirius) and star altitude. I also know RA (right ascension) and Dec (declination) ...
5
votes
1answer
101 views

Why do planets tend to rotate in the same direction although they have formed from tumbling asteroids?

The axial tilts of asteroids seem to vary randomly (let me know if this premise is wrong), while the planets have a strong tendency to rotate in the same way. If planets were formed by colliding ...
4
votes
2answers
93 views

Why are stars more metallic closer as you move closer to the galactic bulge?

As I see it, most of the stars in the galactic bulge are Population I stars. However, as one moves farther from the galactic bulge, star metallicity decreases. In fact, halo stars are almost entirely ...
1
vote
1answer
33 views

Red dwarf variation in Luminosity

I recently saw this video. The creator of the video says that one of the reasons for non-existence of life on planets around red dwarfs might be that these stars can increase luminosity roughly by a ...
0
votes
0answers
6 views

Is there really no difference between up and down in ISS? [migrated]

ISS is actionally falling towards the earth and therefor they don't feel gravity. But ISS is falling in a direction towards the earth. So the astronauts living in ISS probably live in ISS in a manner ...
2
votes
0answers
59 views

How can a naked singularity be possible?

How can we have a singularity, without a black hole around it? How would one form? What does it do?
2
votes
0answers
22 views

Astronomy Jokes [migrated]

Disclaimer: I battled with myself for a few days over whether it would be a good idea to post this question on Astronomy SE. Inspired by Jon Skeet Facts question on Meta SO, I decided to go for it. ...
3
votes
3answers
58 views

Good textbooks for a descriptive astronomy course

Brief tale of woe My department at a small public university in the US has decided to begin offering a descriptive astronomy general education course for the first time in a couple of decades and we ...
6
votes
1answer
113 views

Could an impact have resurfaced Venus 300 million years ago?

Venus surface isn't older than about 300 million years. The only explanation I've come across is that some kind of global volcanism resurfaced the planet. But couldn't it have been an impact event? A ...
0
votes
0answers
29 views

Angular Separation

Two stars A and B are located on the celestial equator. The RA of star A is 02h 0m 00s and that of star B is RA 07h 00m 00s. What is the angualar seperation between star A and B?
4
votes
1answer
83 views

Could Venus or Mercury have a moon that we haven't detected?

Let's consider Mars' two moons for a moment. They're small, not even spherical, and most likely are captured asteroids. They weren't discovered until the late 1800's. Telescopes are much more powerful ...
6
votes
2answers
76 views

Why argon instead of another noble gas?

I noticed that the atmospheres of Earth and Mars have a little bit of argon in them (1% to 2%). I checked Venus, too, which has 0.007% argon, but that's still more than any other noble gas in the ...
10
votes
7answers
9k views

Did atoms in human body indeed come from stars?

I think I am not alone who saw videos about that we (humans) are made of same atoms which someday were in stars. In other words, some atoms in our bodies are from stars which exploded billions of ...
11
votes
4answers
3k views

Is the Earth going to evolve towards Mars' fate or Venus' fate?

Upon reading on this site (and many others), one can think that Mars might have supported life in a distant past (discovery of liquid water, valleys, mountains...). On the other hand, Venus is the ...
4
votes
3answers
385 views

Where can I find a set of data of the initial conditions of our solar system?

As title suggests I'm in need of a set of data of our solar system. Similar to this http://bima.astro.umd.edu/nemo/archive/#iau25, specifically dubinsky milky way-andromeda data. I'm creating a ...
3
votes
1answer
23 views

Where can I find/visualize planets/stars/moons/etc positions?

What resources are available to find the positions of planets, stars, moons, artifical satellites, asteroids, and other heavenly bodies?
7
votes
1answer
217 views

Orbits in a binary star system

I know of three sets of stable orbits in a binary star system: orbiting closely around star A, orbiting closely around star B, or orbiting distantly around both stars (and their mutual center of ...
7
votes
2answers
119 views

Lack of objects between heliopause and Oort cloud?

If we take a look at a logarithmic scale of the Solar System, there appears to be a large gap between the heliopause and the Oort cloud: Why is that? There are some objects in the gap, but why are ...
4
votes
3answers
109 views

Why wasn't there any oxygen in the beginning of the earth?

In the total beginning of the earth there was CO2, N2 and H2O. So there was O2 but always in bond with Carbon and hydrogen, but what is the reason for that? Is O2 always reacting with free ...
4
votes
1answer
34 views

What accounts into calculating the Hubble constant?

From my understanding, the Hubble constant $H_0$ calculates from observed redshifts $z$ of distant galaxys against their proper distance $D$. The current value appears to be 67.80(77) ...
1
vote
1answer
57 views

Where is the materials of comet after it crashed into the sun?

If a comet crashes into the sun, where will the substance (eg: water,silicon) be? Will they be inside the sun? Or they will be ejected from sun again?
3
votes
1answer
76 views

What Would it Look Like Inside Jupiter's Great Red Spot?

From what I've read, Jupiter's 'Great Red Spot' is an unbelievably powerful storm. Do astronomers and scientists have any idea of what that might look like if it were possible to be inside/below it? ...
-6
votes
1answer
51 views

Best planets profile for a tattoo of the solar system [closed]

I want to get a tattoo of the solar system. The gap between the planets should not be preserved and the differences in sizes will only be symbolic. I found the following My question is if all stars ...
3
votes
0answers
31 views

Is there an objective difference between space expansion and reduction in speed of light

I just read an article about the cosmological model of an inflationary universe. As you probably know it basically states that space itself is subject to an expansion over time. Since there is no ...
1
vote
0answers
63 views

are modern flat earthers still believe the earth is flat not round? [closed]

I saw a video in youtube and read few articles about how flat earthers believed that earth is actually flat but not round. They even presented facts about how everything which is true right now is ...
1
vote
1answer
53 views

What is the distance of earth from 7 planets, moon and sun at a point of time?

I wanted to know the distance of the 7 planets(mercury, mars, venus, jupiter,saturn, uranus, neptune) each (or at least 5 planets) from the earth and the angle that it will make with a line connecting ...
4
votes
2answers
104 views

How/where to check where the Sun is (constellation)?

I would like to check in which constellation the Sun was in at some time in the past, any recommendations how to do that?
2
votes
0answers
35 views

How to read Babylonians' tablet that were used to track Jupiter's movements?

There is a science news article on how Babylonians used geometry to track Jupiter’s movements. Here is an image of cuneiform tablet which shows Jupiter's movements. From a layman's point of view, ...
2
votes
1answer
74 views

When is it a good aproximation to consider a star to be an ideal gas?

I am currently taking a first course on stellar astrophysics, and I noticed that in some cases we use the ideal gas equation of state for stars, so we also use $\gamma =5/3$. Of course it can only be ...
5
votes
1answer
63 views

Is Ceres in the inner solar system or outer solar system?

Do we consider the dwarf planet Ceres to be in the inner solar system or outer solar system (or possibly neither / in between). It is located within the asteroid belt, but is the asteroid belt part ...
-1
votes
0answers
52 views

How would FTL travel appear through window of ship? [migrated]

How would faster-than-light travel appear through window of a space vessel? All the movies and TV shows like Star Trek and Star Wars seem unrealistic: Star Trek credits: passing stars get bigger ...
0
votes
0answers
30 views

Does any satellite communicate only through laser? [migrated]

I have read (here) + heared (on astronomy podcast) that radio waves decay or are undistinguishable the more distance they travel. Do any of man made satellites communicate with Earth solely by ...
1
vote
1answer
43 views

What is “emission measure”?

Many papers mention emission measure, and some of them give the expression of EM, BUT there is no clear definition of EM. My question is what EM is on earth? Its unit is supposed to be cm-3. How to ...
7
votes
1answer
109 views

Why don't storms on gas giants move to the poles, like hurricanes on Earth do?

On Earth, hurricanes usually move from the equator to the poles. But if you look at a picture of Jupiter, you'd see that the Great Red Spot isn't anywhere near the poles. So the question is: why don't ...
4
votes
1answer
63 views

At what size to objects burn up in the atmosphere when falling from orbit?

As the title suggests, I am wondering the maximum size an object can be so that it will completely burn up when entering and falling through earths atmosphere. I'm focusing on man made objects, not ...
5
votes
1answer
40 views

What are the prerequisites for a meteorite to reach the ground?

I'm sure it's a function of atmospheric entry angle, meteorite mass (and possibly composition/density), and its velocity, but what function is it? Above all, how does it depend on velocity? Will the ...
1
vote
1answer
41 views

What effect does a natural satellite have on a planet's rotation and revolution?

how is the rotation and revolution of a planet that does not have a natural satellite different from a planet that has say 1 natural satellite (ex. earth and moon system).
7
votes
4answers
190 views

Why does it make sense to say the universe has no centre?

If we suppose we and everything in the universe is perfectly flat. That is, we have width and depth, but no height. And we are situated on the surface of a balloon blowing up with air and expanding ...
-6
votes
0answers
83 views

How old was “student-Earth” when life first formed? [closed]

this section is meant to explore the relative timings of various important events in Earth's history by re-imagining Earth as a 20-year student. You will need to scale geologic time from the age of ...
-2
votes
0answers
28 views
3
votes
1answer
34 views

Where's the Prime Meridian of celestial coordinates

...or what's the 'direction of vernal equinox'? For both Ecliptic and Equatorial coordinate system, the Wikipedia article gives "Primary direction (0° longitude)" - "Vernal Equinox", linking to ...

15 30 50 per page