12
votes
1answer
84 views

Loss of atmosphere on Mars

If the atmosphere on Mars was once much thicker, how was it likely lost? Was it due to interaction with the solar wind, the small size of the planet, both, or something else, and approximately how ...
12
votes
2answers
462 views

Why does a planet rotate and revolve?

Why do planets rotate and revolve in the universe?
12
votes
2answers
308 views

Will an observer falling into a black hole be able to witness any future events in the universe outside the black hole?

I know someone or something sucked into a black hole could not survive, but is the bending of light so immense that an observer falling into a black hole will be able to witness any future events in ...
12
votes
1answer
293 views

What is the object in this photo?

What object is in this photo? View coordinates: $47.25103 \ \ 38.81697$ Time: $2013$-$11$-$23 ~21$:$00 +4 ~UTC$ Sony $A580, \ 50mm f/1.4 15"$
12
votes
1answer
382 views

Do we get any benefit from being in a galaxy?

If our solar system were to somehow be created outside of a galaxy as a single star in the vast nothingness between galaxies, would life on Earth change any? Does being a member of a galaxy actually ...
12
votes
1answer
97 views

How was Io not torn apart by tidal forces during its formation?

Jupiter's moon Io is arguably one of the most volcanically active bodies in the Solar System. The reason, according to NASA's page Scientists to Io: Your Volcanoes Are in the Wrong Place is believed ...
12
votes
1answer
279 views

Magnetic fields of peculiar HgMn A type stars

Do HgMn (peculiar A type) stars really possess global magnetic fields? See, for example, this paper by Hubrig et al. from 2012.
11
votes
7answers
1k views

Do we know the exact spot where big bang took place?

If you rewind the universe back 14,7 billion years, all matter were in one spot, and then started expanding. Do we know where this is in reference to our own solar system? And is there anything there? ...
11
votes
4answers
355 views

What is the most extreme weather found on another planet?

On Venus, there is really inhospitable weather, as well as within the gas giants in our solar system. Are there examples of even more extreme weather on planets found in other solar systems than ours? ...
11
votes
2answers
2k views

Is Earth unique in its fairly clear atmosphere?

So, we have surface pictures from two alien planets, Venus (captured by the Venera 13), and Mars (captured by the rover). Both of these pictures appear to be very dusty. For Venus we see strong ...
11
votes
4answers
221 views

What is the orbital path of the newly discovered star-less planet PSO J318.5-22?

Recent results from Institute for Astronomy at the University of Hawaii at Manoa claim that there is a Jupiter-sized gas giant planet that is independent of a star about 80 light-years from Earth. ...
11
votes
4answers
317 views

How would I measure that I'm at a pole?

How would a person measure that he is at a planetary pole? My first inclination is to use a sextant to ensure that the Sun remains at a constant inclination. However, due to the orbit around the Sun ...
11
votes
2answers
571 views

How many galaxies have been discovered?

I know Andromeda is our nearest galaxy. But how many known galaxies have been discovered and what are they?
11
votes
3answers
534 views

Why are orbits elliptical instead of circular?

Why do planets rotate around a star in a specific elliptical orbit with the star at one of it's foci? Why isn't the orbit a circle?
11
votes
4answers
856 views

How does Titan maintain the atmosphere

Titan which is smaller than mars has an atmosphere but mars is not able to maintain atmosphere. Even Luna doesn't have an atmosphere.
11
votes
1answer
295 views

If we count Avogadro's Number of stars that are closest to Earth, how big that space would be?

I posted this as a question to Scientific Imagination (Area 51 proposal) a while ago. And it was suggested that this question "is perfectly acceptable on Astronomy SE", since "it's about stellar ...
11
votes
2answers
238 views

What is the evidence that galaxies rotate?

Do all galaxies rotate? If so, do they rotate in the same direction? What observations have been made of galaxy rotation?
11
votes
1answer
199 views

Why Jupiter's Great Red Spot is Reddish?

The Great Red Spot is a persistent anticyclonic storm, 22° south of Jupiter's equator, but why is it reddish? From Wikipedia: It is not known exactly what causes the Great Red Spot's reddish ...
11
votes
4answers
9k views

What is the difference between our time and space time?

I am trying to understand the phenomenon of space-time. But, everything on internet seems to be too complicated for me since I do not have a background in physics. Can anyone give me simple ...
11
votes
2answers
487 views

How exactly is our universe mapped?

Watching this youtube video shows that our planet is nothing more than dust in the wind. At the 2:50 mark in the video, you will see a view of the whole Milky Way. At the bottom you will see this ...
11
votes
1answer
1k views

Do star remnants actually burn?

As we know, some stars can fuse heavy elements to produce carbon and oxygen after using up hydrogen if they are massive, and the remnant of stars are usually hot, my question is, if a star fuse to ...
11
votes
3answers
499 views

Is it possible to measure galactic red shift using consumer telescope equipment?

I was wondering if it would be possible to measure red shift from distant galaxies using consumer grade telescope equipment and spectroscopy filters. (like this one) I imagine it would require a ...
11
votes
3answers
2k views

Jupiter FM - What are practical and inexpensive ways for the amateur detection of signals from Jupiter, especially of the transit of her moons?

What modifications to a standard AM/FM or shortwave radio are needed in order to be able to detect radio-wave signals emitted from Jupiter? Would it be possible to detect the transit of the major ...
11
votes
7answers
10k 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
2answers
268 views

Hypothetical beyond Neptune far away planets orbiting the Sun

The planet HD 106906 b was found at 650 AU from its home star, which is not a star much different from the Sun. Fomalhaut b is also a young planet that is orbiting very far away from its sun. These ...
11
votes
3answers
390 views

Calculate Distance To Stars

I was just watching a lecture from Carl Sagan. He talked about figuring out the distance to the stars; it got me interested in learning more about the subject. As far as I know, the Inverse square ...
11
votes
3answers
114 views

Frequency of gravitational wave detection

You may have heard in the news that the LIGO experiment recently detected a gravitational wave. Though I'm not an astronomer, the paper is a good read and mostly accessible. The detection of the ...
11
votes
2answers
520 views

Is it possible to break apart a neutron star?

I was inspired by this question on Physics, as well as this question right here on Astronomy. Neutron stars are tightly bound together as neutron degenerate matter. They're very massive and have a ...
11
votes
1answer
228 views

How did scientists determine an estimate of the number of planets greater than Sedna's size to exist in the Inner Oort Cloud?

In the article, New Dwarf Planet Found at Solar System's Edge, Hints at Possible Faraway 'Planet X' (Wall, 2014) where they report on research and observations performed by astronomers that discovered ...
11
votes
3answers
853 views

How can the 13.8 billion years old universe have a radius of 46 billion light years?

The universe is about 13.8 billion years old. Assume at the big-bang it starts from a small region and the maximum possible speed according Einstein is the speed of light how can the universe got a ...
11
votes
3answers
235 views

Metallicity of Celestial Objects: Why “Metal = Non-metal”?

Metallicity of objects refers to the amount of chemical elements present in it other than Hydrogen and Helium. Note: The other elements may or may not be actual ...
11
votes
3answers
686 views

Is there any point on earth where the moon stays below the horizon for an extended period of time?

When I was teaching a class why the earth has seasons today, I mentioned how the poles of the earth experience months of daylight and darkness. Then one of my students asked whether the moon ...
11
votes
1answer
2k views

Is there any telescope on Earth that can see the lunar rovers on the moon?

If I have the right numbers, it seems to me that even Hubble telescope might barely be able to make out a carcass of a blue whale on the surface of the moon, which puts objects as small as the lunar ...
11
votes
1answer
8k views

How many sun-like stars are there in the universe?

After yesterday's announcement of the Kepler telescope finding a huge amount of newly observed exoplanets, i saw a headline claiming that as much as 22% of sun like stars in the universe have planets ...
11
votes
1answer
405 views

How Does a Refractor Telescope Work?

As I understand it, the difference between a reflector and a refractor is that a reflector uses mirrors on the back to reflect the light to the secondary mirror then the secondary mirror reflects the ...
11
votes
1answer
263 views

Parking a telescope at a Lagrange point: is this a good idea from a debris point of view?

The James Webb space telescope is supposed to be located at the Earth-Sun L2 Lagrange point. Do we expect the region around that point to have a higher concentration of space debris, asteroids, ...
11
votes
1answer
211 views

Why does the Moon seem larger when it is close to the horizon? [duplicate]

I've noticed that when I look into the sky at night, sometimes the moon appears very large near the horizon. Sometimes it also looks like it has a yellow tint. Is this the light rays bouncing off ...
11
votes
1answer
89 views

How is the first detonation in Supernove type Ia triggered?

Ok, I read about the Supernova of type Ia and I found out that there are two detonations happening. First one is in helium shell around the white dwarf and second one seems to be triggered by the ...
11
votes
2answers
460 views

Is there a ninth planet?

After Pluto's demotion as a planet, we have currently eight planets in our solar system. But Sun's gravitational pull can be felt well beyond Pluto, so is it possible to have a ninth planet beyond ...
11
votes
1answer
297 views

Name of area close to Local Bubble?

The following image is a map of the area surrounding the Local Bubble. One side of the image is 1700 lightyears. From the Sun to the Hyades (immediately below the sun) it is 150 lightyears. The local ...
11
votes
2answers
825 views

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 ...
11
votes
1answer
333 views

Why does the Moon stablize Earth's axis?

In an academic study titled 'The Moon and the Origin of Life on Earth' it is said that 'If the Moon did not exist, the orientation of the Earth’s axis would not be stable, and would be subject ...
11
votes
1answer
255 views

Can any information leave a black hole?

Referring to this question, is there any information that can leave black holes? Are they causing a permanent information loss in our universe?
11
votes
1answer
764 views

Is there a limit to how hot a star can be?

I think that size and mass do not correlate to temperature, but then again these factors contribute to the internal pressure. I would like to know if there is a limit to how hot a star can get and ...
11
votes
1answer
314 views

Can we see the Big Bang happen if we look far enough?

The observable universe is constantly expanding as more light from the Big Bang reaches us. This light has been travelling for billions of years, so we are looking at the universe as it was a few ...
11
votes
1answer
353 views

If the moon wasn't receding from Earth, what would be the impact on the weather and tides?

Moon is slowly receding from Earth, which means that after its formation it was much closer to the Earth than now. How would weather look like if it wasn't receding at it would be now as close as at ...
11
votes
1answer
576 views

Explaining Dark Matter and Dark Energy to layman

With my little knowledge, I know this: Dark Matter The center of a galaxy controls/attracts its objects (stars, planets, comets etc.) towards itself because of gravity. But the mass of the center of ...
11
votes
2answers
400 views

How are Galaxy Super Clusters Generated

I have seen pictures of clusters of galaxies, usually used in regards to theories of dark matter and galaxy formations. One of the most famous ones has the perceived shape of a stick-figure. If I am ...
11
votes
1answer
182 views

What are the current observational constraints on the existence of Nemesis?

Nemesis is a hypothetical companion to the Sun on a very eccentric, long-period orbit. The star supposedly returns every few tens of millions years, driving comets into the inner solar system and ...
11
votes
2answers
119 views

Relativistic effects in stellar dynamical systems

I am curious, if anybody knows of any stellar dynamical systems/environments, where relativistic effects could play a dynamical role on the motion of these stellar systems? As a subquestion - are ...

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