0
votes
1answer
89 views

Calculate Day of the Year for a given date

I am trying to make sense of the following formula that claims to calculate the day of the year given today's date represented by (day/month/year): ...
1
vote
2answers
87 views

Do heavier elements breakdown during supernova?

Heavier elements like gold, uranium etc. are formed at the end of a star's life. As the star explodes into a supernova, it gives rise to nebula which is the birthplace of new stars. But as the star ...
3
votes
1answer
79 views

Sun from SuperNova

I have read that our sun was created from older star(s) which had exploded in a supernova. If all the matter is travelling away from the central point of explosion, how does it coalesce back into a ...
30
votes
4answers
5k views

Is the moon only 60 pixels?

In doing research on vision, I have learned that "20/20" vision corresponds to a visual acuity of being able to resolve details 1 arcminute in size, that most people have around 20/15 vision, and that ...
0
votes
0answers
32 views

Triangular Asterism Trigonometry

Using the SIMBAD database for Alnitak, Saiph, and Sirius -- i.e.: Alnitak: FK5 coord. (J2000): RA = 05 40 45.527 DEC = -01 56 33.26; Saiph; FK5 coord. (J2000): RA = 05 47 45.389 DEC = -09 40 10.58; ...
3
votes
1answer
80 views

Motion of the sun as observed from mercury

I recently found this animation which shows the motion of sun as observed from mercury. It seems as if the sun stops in between, retraces a bit and then continues towards the west. What is the reason ...
1
vote
0answers
52 views

Faster Earth spinning speed to overcome gravity, possible? [closed]

As far as I know we stick to the surface of the Earth as its gravity is pulling us and Earth rotation is in a way reducing the gravity. At what speed should Earth be spinning so that we all get ...
1
vote
1answer
79 views

Why planet's orbit is not perpendicular or random ?

Why planet's orbit is not perpendicular or random ? It always seems each planet is revolving on the same geometric-plane around the star.
1
vote
1answer
46 views

How often do stars form?

There are many more stars in the universe than the years that the universe has been in existence, so wouldn't this mean that stars were/are forming at an astounding rate?
0
votes
1answer
74 views

Can Mercury hit Earth or Mars in the next 5 billion years?

Mercury is the most unstable planet of the solar system, with an oscillating orbital eccentricity (between 0 to 0.45). It seems there is a 1% probability in the next 5 billion years Jupiter and ...
0
votes
2answers
50 views

Is dust extinction/reddening caused by Rayleigh scattering or some other physics phenomenon (or both)?

I know from Rayleigh scattering that in the atmosphere redder photons are scattered less than bluer photons by the particles that both make up and are floating around in the atmosphere. This is why ...
4
votes
1answer
61 views

Red cresent moon

Yesterday night i witness something very strange when i looked outside the window. I saw the moon (crescent) but it was dull red and right on the horizon ,which is strange considering that it is ...
0
votes
1answer
79 views

How do we find the exact temperature of a star/galaxy?

This is a very basic question, but I am a little confused. As far as I know, the temperature of a star is analyzed based on the color of the light it emits. So, if a star is moving away from us, then ...
4
votes
2answers
69 views

Can we find out whether early Venus was Earth-like or not?

It has been speculated that Venus billions of years ago could've had a much different atmosphere with liquid water on its surface and possibly life. Partly thanks to the cooler young Sun. But is it ...
8
votes
1answer
78 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 ...
1
vote
0answers
34 views

Intrasolar planetary surface temperature change divergence from Earth

Considering the vast amount of insulating gas emitted by human activity on Earth without a coincident release on all other planets in the solar system as well as the phenomenon that planets in a solar ...
7
votes
3answers
165 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.
1
vote
1answer
57 views

Why do we not find larger quantities of helium in the Sun's atmosphere?

The Sun currently shines because H is being burned to He, and it has been doing this for about 4.57 Ga. But when we analyze the Sun's atmosphere, we do not find unusually large amounts of He. Why not? ...
16
votes
3answers
4k views

What would happen if an ice cube is left in space?

Recently I boarded a flight and noticed Outside air temperature as -53°C at an altitude of 36860ft(11.23km). I don't know what causes such a freezing temperature in that altitude but was wondering ...
4
votes
1answer
86 views

Cooling of stars

If all stars suddenly stopped producing heat (or heating up) which stars would cool to absolute zero first and how long would it take?
1
vote
0answers
39 views

How exactly can the hypothetical conformal invariance of the CMB spectrum be established by analyzing tensor modes?

In the introduction of this paper at the top of p11, it is mentioned that a hypothetical enhancement of the scale invariance of the CMB spectrum to conformal invariance could potentially be ...
-1
votes
1answer
84 views

Does science need support from religion or philosophy to explain the creation? [closed]

Science is trying to explain how the universe is made. The beginning of the universe explains the Big Bang theory. But what happened before Big Bang? Science cannot go before that. So, does this mean ...
1
vote
1answer
116 views

Are neutrinos affected by gravity fields?

Am asking if a neutrino can be pull by the gravity field of a quasar or a black hole, assuming the neutrino have momentum. It could be possible in the that a neutrino can orbit a black hole at an ...
3
votes
1answer
45 views

which or what kind of star has a very stable luminosity?

I mean those kind of stars should be very stable and barely have activity. Their light curves should be very very flat. Our sun, as a G type star, are not so stable. At lest there are lots of ...
2
votes
1answer
101 views

In the end what is the ultimate matter/element in the universe, due to fusion process in stars?

We know that, in stars, hydrogen is used by the stars and due to the fusion in two hydrogen elements we get helium -> Carbon -> Oxygen ->Other elements -> Iron -> then Super/Hypernova. If everywhere ...
-2
votes
1answer
50 views

Big Bang Thoery, what triggered it and why [closed]

Given the vast infinite nature of universe, billions of worlds, distances and masses that we cannot comprehend, do you feel Big Bang theory is inadequate and in some ways tells you that it was all ...
2
votes
1answer
68 views

How would Alpha Centauri A appear from the surface of Alpha Centauri Bb?

I'm trying to imagine what a hypothetical observer on the surface of Alpha Centauri Bb would see in the daytime sky. I know it would vary depending on the orbit of b around B, as well as the position ...
0
votes
1answer
29 views

Do contracting objects show redshift?

If we consider a point on the central part of a contracting object as observed from earth, the point is continuously moving away from us as the object contracts. Moreover, light emerges from a deeper ...
5
votes
3answers
134 views

What shape are black holes theorized to be?

I have always been curious about what black holes (or their event horizons) would look like if we could directly observe them. I notice that they tend to be depicted as flat holes in space but it ...
0
votes
1answer
39 views

Sources of astronomy-related dataset?

I'm doing a project for a statistics class, and I thought it may be interesting work with a dataset associated with astronomy. I know absolutely nothing about astronomy, unfortunately, and I wouldn't ...
1
vote
2answers
106 views

How can a Blackhole have mass?

It is said that in Blackhole 100% part of the mass is getting converted into energy. Then how come Blackhole is having mass ?
2
votes
1answer
85 views

Would a Phobos full impact make Mars temporary habitable?

Due to tidal deceleration, Phobos is predicted to be destroyed by Mars in the next 30-50 million years either by collision or by breaking up in a planetary ring. If Phobos falls on Mars in one piece ...
4
votes
1answer
116 views

How small can a planet be and still have Earth-like gravity?

A planet made from denser material than Earth might have equal gravity to Earth but a smaller radius. How small can a planet be and still have Earth gravity? Ideally it should be habitable by humans, ...
6
votes
2answers
1k views

If Earth didn't rotate, would we feel heavier? [closed]

Suppose the Earth's rotation slowed for some reason. Would the lack of centrifugal force cause us to feel heavier than normal? Likewise, if Earth's rotation increased, would we feel lighter as ...
1
vote
1answer
59 views

Why is Mars' atmosphere so thin?

Is it because there isn't life to exhale enough oxygen and carbon dioxide? The size of Mars is about the same as Earth, so isn't there enough gravity to hold enough air?
5
votes
1answer
65 views

Would space-faring vehicles in interstellar space be in pitch darkness, show reflections from the nearest star or be bathed in light completely?

This is not a science fiction question, but I was considering the visual accuracy of ships in space depcicted in Battlestar Galactica and the like. They are always strongly lit. If they are in ...
2
votes
1answer
75 views

Hamiltonian of general three body problem

i try to extend my analysis from planar restricted three body problem to the general one. Is there anyone that can help me to find out the Hamiltonian for this prolem in cartesian coordinates? I ...
2
votes
1answer
27 views

Does Doppler shift affect apparent pulsar frequency?

We know that redshift and blueshift is the result of the frequency of light waves reflected or emitted by an object lengthening or shortening due to the relative velocity of the observer moving away ...
2
votes
1answer
137 views

How can the sun burn without oxygen?

Allright I am a 17 year old student, that only just figured out that the universe is amazing! Thanks to Dr. Neil Degrasse Tyson I raised a lot of interest in the universe. Due to his latest show ...
0
votes
1answer
30 views

is pan-starrs' data available to public users?

Anybody knows that? The data products are all images or star catalogs? This is the link: http://pan-starrs.ifa.hawaii.edu/public/
0
votes
1answer
49 views

What is visible light colour output of different stars?

I know the colours of the stars relate to their heat, however if I were standing on a different planet identical to Earth, but orbiting a blue Bright Giant or a Red Giant, or perhaps even a Red Dwarf, ...
3
votes
1answer
84 views

What determines which frequency range a radio telescope has?

My simple understanding is that a parabolic dish focuses radio waves to a receiver. It is obvious that any parabola focuses visible light and heat, so I assume that it focuses all radio wavelengths ...
5
votes
1answer
79 views

Is Sahara desert a good place to build radio/optical telescopes?

At least Atacama Desert of northern Chile is a good place to build telescopes. VLT and ALMA locate there. What about Sahara desert? http://en.wikipedia.org/wiki/Atacama_Large_Millimeter_Array ...
1
vote
2answers
90 views

Will a new planet form if Jupiter's influence on asteroid belt will diminish in a few billion years?

I know that tidal forces are pushing Jupiter farther from the Sun, but I couldn't find exactly the yearly amount. In a few billion years would this effect (and subsequent decrease in gravity pull) ...
1
vote
2answers
98 views

Is it dark inside a black hole?

Assuming you could be standing inside a black hole, would it be light or dark around you?
1
vote
1answer
31 views

Jupiter's magnetosphere interacts with the one from Saturn?

Jupiter's magnetosphere extends "seven million kilometers in the Sun's direction and almost to the orbit of Saturn in the opposite direction" and Saturn's magnetosphere extends towards the Sun on ...
2
votes
2answers
65 views

If the moon still had a magnetic field how long would have been possible to keep an atmosphere?

Let's assume the Moon had a considerable magnetic field to prevent the atmosphere dispersion caused by solar wind. Given the low gravity of the Moon, how many years would pass before all the gases (of ...
1
vote
2answers
74 views

Is the surface of Venus red hot?

I was wondering, is the surface of Venus so hot that it would glow red in the dark (e.g. on the dark side of Venus)? I am working on making a solar system simulator, and that would make for a great ...
3
votes
1answer
64 views

Could an asteroid impact cause radioactive fallout?

Could a (regional or global) fallout of radioactive material be a "bonus" disaster effect of an asteroid impact? My reasoning for how such a scenario maybe could be possible: A) Some asteroids maybe ...
2
votes
1answer
38 views

Is the local group bound to the Virgo cluster?

The virgo cluster is currently red-shifted by 0.003 according to Wikipedia; this indicates that the cluster is expanding. Will the cluster's enormous gravity eventually "win" and pull the milky ...

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