8
votes
2answers
184 views

Will new stars stop forming at some point of time?

New stars keep forming in the universe thanks to all the nebulae. Now, we need Hydrogen to form stars and there would a time when all the hydrogen will get exhausted, and no more star formation will ...
8
votes
1answer
141 views

Changes to Earth's orbit

Any time a spacecraft comes in close proximity to a planet and if the spacecraft has the right angle then it is able to use the planet's velocity to move itself further into space. According to ...
8
votes
2answers
100 views

What is radiation pressure and how does it prevent a star from forming?

This is a follow up to: Is there a theoretical maximum size limit for a star? The answer there talks about the radiation pressure preventing a star from forming. What reaction is causing this ...
8
votes
1answer
113 views

How old is our sun in galactic years?

A year is measured as the amount of time it takes Earth to orbit the sun once, a galactic year is the time it takes our sun to make one full orbit of the center of the galaxy. In galactic years, how ...
8
votes
1answer
121 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, ...
8
votes
1answer
87 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?
8
votes
2answers
123 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 ...
8
votes
1answer
180 views

Why does a planet rotate and revolve?

Why do planets rotate and revolve in the universe?
8
votes
1answer
69 views

During an eclipse, does the size of the moon and sun match perfectly?

During a lunar or solar eclipse, from our perspective when we look towards the moon and the sun is behind the moon, does it fit exactly? Has anyone calculated the sizes of each in a relative ...
8
votes
1answer
206 views

How do people measure the distance between the earth and the moon?

How do people measure the distance between the earth and the moon? What methods were used? Where can I find the official data?
8
votes
1answer
85 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?
8
votes
2answers
48 views

What azimuth description systems are in use?

For a time, I thought Azimuth is always direction in degrees, 0 for local, geographic north, 90 for east etc. Then, trying to observe moonrise I downloaded an app that gave azimuth in values between ...
8
votes
1answer
107 views

Any possibility for life on moons of planets in our Solar System

We all focused on our moon, to find water or life, or any thing related to life. But my question is, is there any chance for life in moons of other planets in our solar system, others have too many ...
8
votes
1answer
157 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 $A580, \ 50mm f/1.4 15"$
8
votes
1answer
85 views

What Causes the Large Radiation Fields Around Jupiter?

I had heard that the large radiation belts around Jupiter may be formed by liquid metallic hydrogen in (or around) Jupiter's core (which Wikipedia says haven't been observed in labs yet due to the ...
8
votes
2answers
87 views

How do stellar temperatures vary?

The temperature of the surface of the Sun (photosphere) is between 4500° - 6000° Kelvin. Inside the core, it's around 15.7 million degrees Kelvin. In other types of stars (neutron stars, white ...
8
votes
1answer
248 views

Why do the planets in our solar system orbit in the same plane?

(Yes I'm excluding Pluto from this the same way it was excluded for not being a planet) Observing the planets orbit of the Sun they all seem relatively planar and roughly all orbit along the same ...
8
votes
2answers
70 views

Do the orbits of planets change sometimes?

Do planets sometimes wobble and get off their paths? What if an asteroid were to hit it?
8
votes
1answer
83 views

Navigation using moon phases

How to navigate with possible maximal precision using moon phases? The Moon is the brightest celestial body seen in the night sky, and it is possible to find even through moderate clouds. So it's a ...
8
votes
2answers
190 views

Are there a lot of collisions between stars in the core of the galaxy?

I'm reading on Wikipedia about Halo Stars that orbit the center of the galaxy at a high inclination away from the plane of the Milky Way. It seems that at some point, these stars must dive back into ...
8
votes
1answer
71 views

Blowing up an asteroid/comet really potentially worse?

Often on television shows and in articles I see it mentioned that it'd always be bad to blow up an asteroid or comet because then the energy would just be spread out and cause even more damage. ...
8
votes
1answer
84 views

How do scientists know that a rock found on Earth came from Mars?

There are many documented cases of meteorites being reported as from Mars. http://en.wikipedia.org/wiki/Allan_Hills_84001 While I can understand that it's possible to know if a rock originated as a ...
8
votes
1answer
87 views

How do we calculate the escape velocity of galaxies?

How do we calculate the escape velocity of galaxies? Do we have to know the total mass? What is the escape velocity for Milky Way?
8
votes
1answer
520 views

Finding the solar noon based on longitude and latitude?

Please could someone advise the best method of finding the solar noon based upon location? http://pveducation.org/pvcdrom/properties-of-sunlight/suns-position The stuff on here has been helpful but ...
8
votes
1answer
61 views

When will we be able to detect Earth-sized exoplanets?

I have heard that the only planets able to be seen outside the Solar system are Jovian-sized planets with the occasional detection of planets three times the Earth's size. But, as far as I know, we ...
8
votes
1answer
51 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 ...
8
votes
1answer
79 views

Mechanisms of binary/multiple star formation

What are mechanisms of binary/multiple star formation in different mass ranges (low, intermediate and high stellar masses)?
8
votes
1answer
53 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 ...
8
votes
1answer
158 views

How do we detect if a planet has a liquid core?

In case of Earth, we have many hints about the internal structure of our planet, from what I know, the most important of which is analyzing seismic waves. Do we have any instruments to detect if ...
8
votes
1answer
76 views

What is a White Hole?

White holes are purely hypothetical at this point and are considered only because it is assumed something like it could exist as the balance to black-holes. Reading this article seems mostly writers ...
8
votes
1answer
89 views

How many galaxies disappear beyond the Hubble Bubble horizon every year now?

The accelerating expansion of space means that the space between us and far away galaxies expands faster than light can travel through space. There is a horizon of possible observation beyond which ...
8
votes
1answer
268 views

Determining effect of small variable force on planetary perihelion precession

Is there an analytical technique for determining the effect of a small variable transverse acceleration upon the rate of aspides precession (strictly not a precession but rotation of the line of ...
8
votes
1answer
81 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
64 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 ...
8
votes
2answers
78 views

Adjust axis labels in ds9

How can I adjust the axis labels in ds9? I'd like to have something like: So far I only managed to get floating points (tl h%f3): or the leading hours are missing (tl h%f1 m): Edit: I tried ...
8
votes
1answer
66 views

How Does Cosmology Constrain the Number of Neutrino Species?

I've asked this question already on the Physics SE, but I felt it would be worth posting here as well. I know that based upon theories of structure formation cosmologists can constrain the sum of the ...
7
votes
4answers
169 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? ...
7
votes
2answers
355 views

What was the length of year 1 million years back?

We know that the universe is gradually expanding and this indirectly means that the gravitational force between sun, earth, planets and other stars (roughly anything in the universe) is gradually ...
7
votes
4answers
130 views

What will a lunar eclipse look like from moon?

What will a lunar eclipse look like from moon? Will earth become a completely dark circle?
7
votes
3answers
142 views

Why is the interstellar medium so hot?

On this link, it states the following: "large assemblies of galaxies that are permeated by even larger amounts of diffuse gas. With temperatures of 10 million degrees or more". How are these ...
7
votes
2answers
925 views

Can two comets travel together as one?

If two comets come together in space, will they bounce apart, merge into a single body, or could they travel together through space, either touching or orbiting a shared center of gravity?
7
votes
3answers
377 views

By putting a mirror in space, would we be able to see into the past?

I only ask this because of how fast light travels. The question remains in the title. Why, or why not, would this work?
7
votes
2answers
744 views

Why can we sometimes see the moon during the day?

At some points in the year, the moon at my location can be clearly visible during the day. Why is this? If it is any help, I live in Alberta, Canada.
7
votes
2answers
107 views

Moon orbits crossing each other

Some planets, such as Mars, have 2 or more moons. Giants, like Jupiter of Saturn have a lot of moons! How likely the orbit of one crosses another one's orbit? Is it possible for two moons to collide? ...
7
votes
2answers
157 views

How are black holes doors to other universes?

I'm watching MIT OpenCourseWare lectures on general relativity and not too long into the first lecture the professor stated that the Kerr Black Hole solution allowed for travel between universes. How ...
7
votes
1answer
962 views

Are satellites orbiting around earth visible to the naked eye?

I was just lying under the sky trying to possibly see some meteorites, unfortunately never seeing any I might add, but I saw three objects all moving at about the same speed( all at different times). ...
7
votes
4answers
589 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 ...
7
votes
2answers
298 views

Why don't we see the galaxy center?

When we look at the sky, and see the Milky Way, we mainly see a band, with no real center. On a more accurate picture we can guess the center of the galaxy (see this picture), but we still don't see ...
7
votes
1answer
152 views

Is it possible for a moon to orbit a planet floating free in the galaxy rather than orbiting a star

This article got me thinking, can a planet hold a moon in orbit if it is just floating in the galaxy by itself not as part of a star system? Can a celestial body even qualify as a planet if it is ...
7
votes
3answers
168 views

Can impact craters on the moon act like giant radio telescopes?

Could large craters on the moon be used as reflective lenses for radio signals? Acting like a large radio telescope reflecting radio waves to a satellite positioned over the crater.

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