2
votes
1answer
141 views

Are these facts about moon true?

I don't have much knowledge of Astronomy but today I was googling randomly and found an article, according to which: The moon is of the wrong size for its current orbit. The moon rings like a ...
2
votes
1answer
31 views

Speed comparison of both voyagers

I came across this page which provides (mostly extrapolated) speeds of both voyagers. Assuming they are fairly accurate, any reason why the speed of Voyager 2 (5-6 km/sec) is less than that of Voyager ...
2
votes
3answers
108 views

Where can I find a catalog of all stars in the Milky Way?

Is there a catalog of all known stars or brightest stars in our galaxy? Preferably with some sort of galactic coordinates instead of just night sky coordinates (right ascension, etc.) I'm trying to ...
2
votes
1answer
36 views

Triple Stars v/s Ternary Stars

Ternary (or trinary) stars are not the same as triple stars. So, what is the basic ...
2
votes
3answers
86 views

Pulsation Modes of Cepheids

There are various modes of Cepheids like single modes: fundamental (F), first overtone (1O), and likewise. And then we have double modes: F/1O, 1O/2O etc. triple modes: 1O/2O/3O etc. ...
2
votes
1answer
70 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 ...
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 ...
2
votes
1answer
120 views

Black Hole / Hawking Radiation: Why only capture anti-particle?

I may have some specifics wrong here. If so, don't focus on those. Just focus on the general thrust of my question. I "understand" (cough) that particle/anti-particle pairs form spontaneously in ...
2
votes
1answer
168 views

What would happen if Jupiter and Earth were at the same distance as the Moon is from Earth?

If Spock came with a super machine capable of moving planets, and placed Earth so close to Jupiter as the Earth's moon, the gravity of Jupiter would make us fall into it?
2
votes
2answers
113 views

What is the temperature of outerspace?

I want to know whether the temperature in Outer space is higher than earth's or cold.Is the temperature in outer space vary as it does on earth?
2
votes
2answers
101 views

What mechanism causes oscillations of the solar system's orbit about the galactic plane?

In a recent paper (news release here) Lisa Randall and Matthew Reece propose that a dark matter disk coinciding with the galactic plane together with the solar system's oscillations through the ...
2
votes
1answer
96 views

What exactly does outer space contain?

Does outer space contain any gases? Recently i watched a video on youtube,in which NASA installs a camera on a spacecraft.The footage shows some dust particles or some matter floating over the space ...
2
votes
1answer
83 views

What is the orientation of planetary orbits?

I'm working on a planetary motion simulator. I've been working through the equations anomaly, eccentricity, etc. The one thing I'm curious about is if all the ellipses are oriented the exact same way ...
2
votes
1answer
121 views

When did the Moon stop?

According to various theories the Moon was created around 4.5 billion years ago. About all of these theories suggest that it was rotating around its axis at that time though. Currently, Moon is at ...
2
votes
2answers
128 views

What is Event Horizon of a Black Hole? [closed]

The boundary of a black hole is said to be surrounded by event horizon - the point of no return! What is its significance in terms of general relativity?
2
votes
2answers
60 views

regarding curvature of earth [closed]

i am having one doubt in earth's curvature.....this question may be dumb... How much we need to travel on earth to feel the curvature of earth. hypothetical case: for ex we are building a vehicle ...
2
votes
2answers
130 views

Why do objects burn when they enter earth's atmosphere?

Why do all objects burn when they enter our atmosphere? is this because of our atmosphere composition? and does this happen on other planets as well?
2
votes
1answer
79 views

What's the estimated remaining life of Halley's Comet?

I know that Halley's comet is seen from Earth every 76 years or so since a couple centuries. As it travels, and particularly when it comes near the sun, it loses some of its material (ice). Someday, ...
2
votes
1answer
35 views

Why aren't the farthest objects close to each other?

The last years we find some objects like this : MACS0647-JD which are more than 13 billion light-years away from us. This means that the picture we get was created only some million years after the ...
2
votes
1answer
30 views

Time after sunset until star can be seen

Given a star's apparent location and apparent magnitude, how how many degrees below the horizon must the sun be for the star to be visible to the naked eye for an observer on Earth at a specified ...
2
votes
1answer
18 views

Beta profile fit of Virgo cluster gas?

I'm looking for the parameters $r_c$, $\rho_0$ and $\beta$ in a $\beta$-profile fit of the Virgo cluster's ICM density. I just can't find a reference for it. Unlike for Coma (Abell 1656) where it's in ...
2
votes
1answer
46 views

Weight of a celestial body

How do astronomers find out the correct weight of a planet tough there isn't any direct means to weigh them?What technique do they use?Just curious!
2
votes
1answer
51 views

What is CMB radiation doing to the universe?

It is said that due to CMB radiation our universe has been expanding? Firstly what lead the universe to expand? What do scientists mean by dark energy? Will energy convert into matter?
2
votes
1answer
79 views

Visibility of Apollo 11 module

I wasn't around when man landed on the moon in 1969. When I see the moon, I always wonder, were people able to see the rocket? Yesterday, I looked at the moon in daylight and wondered again. My ...
2
votes
2answers
36 views

Can solar luminosity & activity be predicted?

Can a star's luminosity and its activity, solar flares and sunspots, be predicted? If so, with what accuracy & precision?
2
votes
1answer
51 views

What is the time/size/rigidity ratio for a space object to become mostly round?

In the answer here multiple comets are identified that do not form a single round body. A drop of water will form a round shape in the time it takes to free fall a couple of feet. All of the ...
2
votes
1answer
46 views

Metallicity: What are the metallicity values of various galaxies?

What are the various values of metallicity of various known galaxies, like Milky Way, Large Magellanic Cloud, Small Magellanic Cloud, Andromeda and so on?
2
votes
1answer
83 views

If an object with mass were to somehow go the speed of light, would it destroy the whole universe?

Would an object with mass traveling the speed of light destroy the whole universe because it would have infinite energy / mass? According to ...
2
votes
2answers
55 views

How many stars are visible to naked eyes around Equator area?

In the best sky conditions, we can see about 44,000 stars in the sky. But what if I am located around Equator area? How many stars I can see? From what I know, the number of stars I can see should ...
2
votes
1answer
89 views

Average amount of annual daylight at any place on earth

If this is the wrong group please direct me to the correct one. It seems intuitively obvious that the amount of daylight per annum should be the same for any latitude on earth. For example, 12 hours ...
2
votes
1answer
66 views

What is the optimal escape trajectory from near a black hole?

Consider a space ship that is being drawn closer to a black hole. The crew begins to notice the effects, and discovers that they are nearing the black hole. They then manage to halt their ...
2
votes
2answers
109 views

Why are spacecraft not air-launched from airplanes

I searched on the subject, thinking it could probably be cheaper to fly the spacecraft aboard a plane and then launch it from altitude. The only thing I found was this Wikipedia page, but it only ...
2
votes
2answers
49 views

how to know the nature of the companion in a neutron star binary?

The companion could be a main sequence star, white dwarf, neutron star or black hole. We detected pulsar-pulsar binaryhere several decades ago. But if one of the pulsar does not radiate towards us, ...
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
58 views

Choosing a diffraction grating

I am interested in doing some solar spectroscopy on my own for fun. How do I go about choosing the appropriate diffraction grating?
2
votes
2answers
83 views

Satellite/Planetary Orbits

All planetary orbits contain 5 unusually stable points. These points are particularly important because they allow man-made satellites to orbit the Sun with a period equal to that of Earth’s. 3 of ...
2
votes
1answer
52 views

What is the connection between moons, rings, and gaps?

I was watching this video and they said that the rock probably has a moon. Is the reason they assume it has a moon is because there is a gap between the rings created by the moon's orbit around the ...
2
votes
1answer
44 views

Question about the formation of elements

So, elements such as iron, gold, etc. are formed from different types of supernovas, whether it's type 1A or 2. My question is, is it possible that there are elements that are formed that we never ...
2
votes
4answers
149 views

What is the speed of light relative to (in space)?

From what I understand the universe is expanding faster than the speed of light and accelerating so that it's possible that a given galaxy: $A$ will no longer be visible to another given galaxy: $B$. ...
2
votes
1answer
115 views

How can I calculate the orbital periods in a binary star system?

I have two stars, with known masses and known orbital radius. How do I calculate the orbital periods of both stars?
2
votes
1answer
37 views

What would the sky have looked like when galaxies first started to form?

If I stood on a theoretical earth at the time that galaxies were just starting to form, what would the sky have looked like? Due to the smaller size of the universe would it have been densely packed ...
2
votes
2answers
72 views

Absolute magnitudes of stars

Where to find comprehensive list of absolute magnitudes for stars of different spectral types? I need published paper or web page with data and reference to the source.
2
votes
1answer
66 views

if the big bang only expanded the universe when and how did it originate? [duplicate]

If the big bang expanded the universe from a singularity point, that means that there was matter before, so where and how did matter form for the first time if it's even possible to know such a thing? ...
2
votes
1answer
108 views

If oxygen was abundant in Neptune, would there be combustion?

Since Neptune/Uranus have high percentages of methane, wouldn't it be highly likely that there will be combustion (triggered by the lightning storms or any other factor) if oxygen was abundant? And ...
2
votes
1answer
119 views

If the tilt of the Earth changed, would the tropics latitude change too? [closed]

I wanted to know if the tilt of the earth were changed to 30 degrees would the tropics of cancer and Capricorn also both change to 30 degrees?
2
votes
2answers
159 views

the most accurate system that can show the positions of planets at my birthday [closed]

My birthday : 4 December 1982 If you have such astronomical calculator on your computer please send me the result ! Alternatively if you know an online astronomical service for my purpose please ...
2
votes
2answers
45 views

How do kepler orbits account for planetary migration?

This article got me thinking if kepler orbits explain how a planet moves in a solar system how can a planet migrate as explained in the article. At some point don't the kepler orbits must need some ...
2
votes
2answers
69 views

Can we conclude with reasonable certainty that there is/are no Type 3 Civilizations in our galaxy?

As per the Kardashev Scale, type-3 civilizations are defined as "civilization(s) in possession of energy on the scale of its own galaxy, with energy consumption at ~ 4 x 10^44 erg/sec". Considering ...
2
votes
1answer
43 views

Data for red-shifting

I am looking for basic data regarding red-shifting that comes with reliable measure of distance of the emitting star.
2
votes
1answer
17 views

Collimator for Dobsonian, same as Newtonian?

I have been looking on line for Collimator for my Meade Dobsonian. The only Collimators I can find are made for Newtonian Lenses. It's a 8" mirror with a 1.25" lens. Will this work for my telescope?

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