11
votes
1answer
128 views

Future of CMB observations: How will our knowledge of the early universe change?

The Planck satellite has been presented and awaited for a long time as the ultimate experiments for measuring temperature fluctuations in the cosmic microwave background (CMB) over the full sky. One ...
4
votes
1answer
37 views

Does the Perseid peak cause enough light pollution to be a problem?

The annual Perseid peak occurs between August 9-14. During this time, about one meteor burns up in the atmosphere per minute. When these meteorites burn up, they generate light. When you have one of ...
14
votes
1answer
152 views

I live in an area with a lot of light pollution, how can I view the stars without building an observatory?

I live in an urban area with a lot of light pollution and very little garden space. On a clear night I can see most of the sky and the brighter stars are visible. I can't build an observatory - I ...
12
votes
1answer
99 views

How often do comets survive passage by the Sun?

I had heard that comet ISON might not survive a close pass by our Sun, and I was curious about the odds of how other comets had fared. So, how often do other comets survive a close pass by our sun? ...
7
votes
1answer
26 views

What observational constraints are there in detecting the presence of volcanism on exoplanets?

This question is somewhat related to my earlier question How are the compositional components of exoplanet atmospheres differentiated?, but this about a specific surface-atmospheric phenomena - ...
8
votes
1answer
78 views

What implications do younger Earth and Moon have on Late Heavy Bombardment genesis hypotheses?

The Late Heavy Bombardment (LHB) or the Lunar Cataclysm is when the inner solar system, including the Earth and the Moon, underwent multiple and sustained heavy impacts early in their history (around ...
8
votes
1answer
50 views

Are any Pluto-sized objects remaining to be discovered in the Kuiper Belt?

An object approximately the same size as Pluto, Eris, was discovered only 8 years ago (in 2005). Are there any Pluto-sized objects remaining to be discovered, and if so, how far away from the Sun ...
9
votes
1answer
83 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 ...
6
votes
1answer
72 views

What are the current observational limits on the existence of Dyson spheres/swarms/rings?

A Dyson sphere/swarm/ring is a hypothetical structure an extra-terrestrial entity would construct to collect a large fraction of its host star's light, and would likely generate a fairly strong ...
7
votes
1answer
79 views

Effect of Charon on Pluto

Even though Pluto is not known as a planet anymore, theroetically it has/had a moon, called Charon. I've heard about something that their size are so close to each other that while Charon rotates ...
3
votes
2answers
42 views

Why did the Chelyabinsk meteor explode?

In February, a meteor entered the Earth's atmosphere over Chelyabinsk, Russia and exploded, producing a shockwave blast that damaged hundreds of buildings around the explosion site in Russia. But why ...
5
votes
1answer
39 views

How far apart is the dust in the Sombrero Galaxy's dust lane?

In his answer to this question, TildalWave made this remark: I think that first, we have to properly appreciate the size of the Sombrero Galaxy. It is roughly 50,000 light years (15 kilo parsecs) ...
6
votes
1answer
122 views

Why is the Moon receding from the Earth due to tides? Is this typical for other moons?

After reading the Q&A Is the moon moving further away from Earth and closer to the Sun? Why? about the tides transferring energy to the Moon and pushing it from Earth, I have a question: How is ...
9
votes
1answer
56 views

What practical considerations are there for amateur observations of transiting exoplanets?

Obviously, I am not referring to actual viewing of the exoplanets themselves, but detecting their effects on the brightness of the light emitted from the parent star (as in the diagram below from The ...
8
votes
1answer
79 views

What is the predominant element in the dust of the Sombrero Galaxy?

The Sombrero Galaxy contains a rather peculiar ring of dust orbiting it (seen as the dark ring on the outer edge). What is the prevalent element in this dust? Carbon?
9
votes
1answer
120 views

What is the current accepted theory for the fate of hot Jupiters?

It is well established that one main feature of many hot jupiters is their close proximity to their parent star, usually the equivalent of being within the orbit of Mercury. So, these planets are gas ...
9
votes
1answer
84 views

Is the surface of TrES-2b actually dark?

The exoplanet TrES-2b is known as the darkest planet ever found, reflecting <1% of the light that hits it. What does it mean in respect to the surface? What would we see below the atmosphere of ...
8
votes
1answer
175 views

Why does a planet rotate and revolve?

Why do planets rotate and revolve in the universe?
5
votes
1answer
67 views

Could there be Earth-like planets in binary or trinary systems?

Could Earth-like (suitable for Human habitation) planets exist in systems with 2 or 3 suns, have any been found? With more than a single star, isn't it likely that the habitation zone would be too ...
14
votes
1answer
119 views

Why is there a matter/anti-matter asymmetry in the universe?

After the big bang occurred what biased the formation of particles over anti-particles? Why are particles more common than anti-particles?
8
votes
1answer
116 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, ...
15
votes
3answers
256 views

Can small gas planets exist?

Most of the known gas planets (Jupiter, Saturn, etc.) are huge. They are even called "gas giants". is it possible to exist a gas planet around the size of Earth? If yes, why; if no, why?
11
votes
1answer
107 views

Has Hawking Radiation Ever Been Observed?

I know Hawking Radiation has firm theoretical footing, but has a signal ever actually been observed? What observational research is being done to attempt to see this effect? Is it simply too tall an ...
8
votes
1answer
61 views

What is the current accepted theory as to why Mercury, despite its size, has a similar density to Earth?

According to the NASA web page overview about Mercury, despite the planet being just a bit larger than our moon, it's density is about 98.4% of Earth's. This high density suggests a comparatively ...
5
votes
1answer
62 views

Why has Moving Cluster Method been successful only for Hyades?

At all places where I have read of Moving Cluster Method for measuring distance to a cluster and once applied myself on data, I have been told that the method has been successfully applied only to ...
12
votes
2answers
222 views

Does the Moon have any oxygen in its atmosphere?

Since the moon has gravity, it's almost impossible that there aren't some gasses trapped on the surface by the moon's gravity. Has any free-floating oxygen been found on the Moon? If so, in what ...
11
votes
1answer
105 views

Have we ever observed a large meteor hit the Moon?

Since the moon has no atmosphere, its surface has many more meteorite impacts than Earth's does. Image source Have we ever observed a meteor strike the surface of the Moon?
6
votes
1answer
272 views

What is the origin of the OBAFGKM classification system?

Once a body has been identified as a star it is classified into a subsection of either O,B,A,F,G,K or M (I think there are also 3 more letters recently added) What is the origin of this ...
7
votes
1answer
55 views

Why does mars appear to retreat across the sky?

If you plot the movement of mars across the Earth's sky it appears to move back on itself during its orbit. Why does it appear to have a loop shape from Earth?
9
votes
1answer
123 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 ...
9
votes
2answers
151 views

How does angular resolution of a telescope translate to its parallax precision?

We can often read in the scientific and also more casual reader literature and articles about the angular resolution of various telescopes and other optical equipment, be it ground based or onboard ...
18
votes
1answer
179 views

How could a hobbyist astronomer determine apparent magnitude of a star?

Apparent magnitude is a rather complex way to determine the brightness of a star. Quoting the introduction text from the linked to Wikipedia page: The apparent magnitude (m) of a celestial body is ...
12
votes
2answers
199 views

Is there a theoretical maximum size limit for a star?

Some stars are simply huge. Eventually, though, wouldn't there be simply too much pressure or mass for the star to sustain itself? Wouldn't it eventually collapse into a black hole? Is there a ...
11
votes
1answer
111 views

Dark Matter Particle Candidates

Dark matter appears to dominate the matter component of the universe as compared to luminous, or baryonic, matter. Though it does not interact electromagnetically (it doesn't absorb, scatter, or emit ...
17
votes
2answers
457 views

Why does Jupiter have so many moons?

Jupiter has a great many moons - in the hundreds, and they're still being discovered. What is the current theory for where all these moons came from? Are they rocks flying through space captured by ...
6
votes
2answers
110 views

Sky photography through compositing images in software?

I've read about and seen some rather sophisticated rigs for night sky photography that allow for ultra-long-exposure photos by counteracting the rotation of the sky by rotating the camera with it. The ...
10
votes
3answers
99 views

What is there in the intergalactic space?

What bodies can be encountered way outside galaxies - far beyond the farthest edges of galaxies, in the deep space between them? Are there single, galaxy-less stars, giant clouds of gas more dense ...
11
votes
2answers
201 views

Space expansion in layman terms

So far I got to understand the expansion of space is not to be understood as stars drifting further apart through space. There's something more fundamental - e.g. you can't simply measure speed of it, ...
7
votes
1answer
60 views

How fast do we travel through space?

Could someone give the rough estimates of speeds of our travel through space? I can easily find the two nearby ones: Earth's own rotation - depending on latitude, up to 40,075 km/24h = 463 m/s ...
8
votes
2answers
78 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?
6
votes
1answer
42 views

What evidence is there of Earth-Like internal features of Europa?

This question is inspired by "What are the Earth-like features of Titan?". According to NASA's Europa overview, Europa is believed to have an iron core, rocky mantle and an ocean under the frozen ...
9
votes
1answer
312 views

Why do some planets have rings?

Some planets, specifically Jupiter, Saturn, Uranus, and Neptune in our solar system, have planetary rings. Why do some planets have rings? How are they made and from what? Most importantly, will I ...
7
votes
1answer
508 views

What is the current theory for the formation of the Earth's Moon?

Given that the Earth and Moon are often said in the literature to have very similar geochemistry, what is the current theory as to how the Earth's Moon formed?
15
votes
2answers
183 views

Why is the Hubble Telescope in space?

Why is the Hubble Telescope in space? Do we get enhanced clarity and range by placing it in space? What can it achieve from space that it could not achieve from Earth?
6
votes
1answer
74 views

What is a hypernova and have we observed any?

Inspired by the question "What does it mean for a star to go nova or supernova? Can I safely observe these?", I am curious about what hypernovas are? Have we observed any occurring, or the at least ...
12
votes
1answer
262 views

What does it mean for a star to go nova or supernova? Can I safely observe these?

What does it mean for a star when people say it goes 'nova' or super nova, what are the differences? More importantly, can I safely observe these with an amateur telescope? I imagine they would be ...
11
votes
3answers
1k views

Does the Sun belong to a constellation?

Each new star we find is generally considered to be part of the constellation it is nearest to. Our Sun is obviously a star, just much closer. Is our Sun part of any constellation? If so, which ...
4
votes
2answers
65 views

What are shooting stars and how are they formed? [duplicate]

What are shooting stars? How are they formed and how often do they occur during the night? Also, why are there more shooting stars on some nights than on others?
2
votes
3answers
96 views

What gases are needed to make a star?

What gases do you need to start the creation of a star, and why do you need these gases? What are their functions?
9
votes
1answer
41 views

How can we detect water on Mars-like exoplanets?

According to data from Curiosity, Mars' dust holds about 2% water by weight This wasn't previously detected, so the impression we have had of Mars being incredibly dry may need to be altered. Okay it ...

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