2
votes
2answers
19 views

Has someone looked the other way?

I learned that gravity always pulls, it is always attractive. There is no antigravity, no "negative" mass. I also learned that most matter is dark, invisible. We know that because we see visible ...
0
votes
0answers
2 views

Special names for lunar things

A blue moon is 2 full moons in a month. What could we call 2 new moons, 2 first quarters, 2 waxing crescents, 2 waxing gibbouses, 2 third quarters, 2 waning gibbouses, and 2 waning crescents in a ...
0
votes
1answer
8 views

Does the Sun have hard radiation?

Does the Sun spreads hard radiation waves around the Solar System? If yes, why are we safe here - are even we?
2
votes
2answers
30 views

Why is Mars considered the outer edge of the “goldilocks zone”?

In both books and documentaries I often see the Goldilocks Zone as described between Venus and Mars with the Earth "just right." This seems sort of ill thought out to me, because it assumes that ...
4
votes
0answers
35 views

Why did NASA intentionally crash the Lunar Atmosphere and Dust Environment Explorer (LADEE) on the moon? [migrated]

The Lunar Atmosphere and Dust Environment Explorer (LADEE) was intentionally crashed into the moon by NASA but why did they crash the craft instead of leaving it in orbit, or was it a part of some ...
-2
votes
1answer
41 views

Relation between position of stars and locations of gemstones? [on hold]

A theory has been said that the patterns and positions help identify where valuable gemstones are hidden. I am wondering if this has any truth in it.
6
votes
1answer
135 views

Why is the solar system often shown as a 2D plane?

Whenever I have learned about the solar system I always see the orbits displayed as a virtually flat plane. Are all of the orbits in the solar system really like this? If so, why? It seems like a ...
5
votes
3answers
59 views

Red Moon a Characteristic of all Total Lunar Eclipses?

I understand that the redness of the moon during the total lunar eclipse last night/this morning (April 14-15 2014) is a reflection of the red light caused in earth's atmosphere due to Rayleigh ...
3
votes
2answers
69 views

Questions about time and space (from beginner)

To be honest my knowledge about astronomy and related physics is close to zero. However, since I studied math a bit, I would like to ask a couple maybe stupid questions, which I am curious about and I ...
6
votes
2answers
88 views

Is it a coincidence that both the sun and moon look of same size from earth?

The sun is huge when compared to moon. Despite the huge difference in their size and distance from earth, Is it purely coincidental that they both look almost the same from earth?
0
votes
2answers
41 views

Putting mass-luminosity relation and HS diagrams together leads us to a mass-age relation; so how do stars lose their mass over time?

I think that the title is completely clear, but here's an expansion: I was just reading about Mass-luminosity relation that says massive stars are more luminous than tiny ones. Well, let's talk about ...
2
votes
2answers
57 views

What is a singularity? What is at the center of a black hole? Specifically regarding space-time

So because I can only really think of space-time in 2-dimensions like a sheet of something, my assumptions might be wrong to begin with. I was watching a youtube video on black-holes and there was a ...
0
votes
1answer
17 views

How are the speed, distance and time of India's MOM and USA's Maven Mars missions calculated?

How do the scientists calculate the correct time to launch the Mars mission so that the satellite travel time is less? How they are synchronizing the speed of satellite with respect to earth and mars ...
2
votes
1answer
23 views

Are there standard algorithms and procedures for creating unique sky maps based on latitude/longitude/date/time?

I am trying to build an astronomy app that will use the user's latitude and longitude, along with the current date and time, to create a 3D view of the celestial sphere as seen based on that data. ...
0
votes
2answers
54 views

How can the universe be infinite?

I've heard from renowned astrophysicists that we don't yet know whether or not the Universe is infinite. How is that possible regarding the big bang theory is accepted (as they all do)? Are they ...
1
vote
3answers
70 views

Why is iron responsible for causing a supernova?

Why is the element iron responsible for supernova? Can any star create more element than iron within the span of its life? I understand that when star dies due to supernova, other elements are ...
6
votes
4answers
138 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 ...
8
votes
0answers
120 views

How exactly does does inflation convert random gravity fluctuations into coherent gravitational waves?

In the course of this very enjoyable press announcement, it is mentioned that inflation can create gravity waves by amplifying gravity fluctuations. I do not properly understand this statement. I ...
4
votes
4answers
185 views

Why is the speed of light 299,792,458 meters/sec?

Ok, I am majoring in physics (4th year) and I never understood this fundamental (kinda) question. Maybe I haven't explored it enough. For example, why does it take 8min20sec for the light from the ...
3
votes
2answers
42 views

Does the earth's atmosphere act as a spherical lens and refract light from space?

If so by how much does it "spoil" the view of stars and galaxies etc. Is this error noticable, when compared to pictures taken from outer space.
3
votes
1answer
43 views

Which type of telescope should I make?

I am not very much interested in observational physics but I just like to look at the night sky. It gives me a lot of inspiration. So, i was thinking about making a telescope for basic observations. I ...
0
votes
0answers
14 views

Maximum Amplitude of a Lissajous Orbiting Object in a L4 or L5 Position

I stumbled on The Lagrangian points during some wikipedia reading. After looking at the gravity contours, I naturally come to the conclusion that the L4 & L5 should have a wave pattern and then ...
3
votes
2answers
83 views

What is the term for a star swallowing another star?

A star A goes through the body of another star B, or is swallowed by B. There is no tidal disruption. It sounds like kerzan. Does anybody recognise this pronunciation?
1
vote
1answer
53 views

Please Guide me to buy my first Telescope

I am a beginner and I've planned to buy a telescope(Newtonian reflector)for viewing planets and deep sky objects. As far as I know the most important factor to get a brighter view is that the ...
3
votes
2answers
183 views

Why are distant galaxies not visible in the observable Universe?

Assuming that the Universe is and has been expanding ever since its creation (Big Bang theory), the galaxies that are now at the 'edge' (not visible theoretically) must have been (at some point in ...
0
votes
1answer
49 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 ...
8
votes
1answer
843 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). ...
1
vote
3answers
96 views

The formation of absorption lines in solar spectrum

It is said that absorption lines originate from regions higher in the photosphere where the gas is cooler. The gas should be absorbing photons, then re-emitting them... absorb, re-emit, absorb, ...
2
votes
2answers
51 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 ...
0
votes
1answer
34 views

Why is the Solar Helical (Vortex) model wrong?

Could someone give a lay description of why the Solar System's depiction of motion as a vortex is wrong? ref: Youtube video The helical model - our solar system is a vortex Please don't take for ...
6
votes
4answers
88 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?
2
votes
1answer
48 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
0answers
24 views

How to use a telescope to find a specific celestial body?

I am a beginner interested in astronomy. I bought a Celestron AstroMaster 130EQ telescope. It's a Newtonian Reflector and it's not computerised. I did manage to see the Moon in some magnifications but ...
3
votes
2answers
76 views

How and when did we learn about the universe?

I'm 13 - I'd like to know how we found/discovered important details about the Universe. I know we have found many different things about the Universe, but when did we find how amazingly large the ...
1
vote
1answer
37 views

Will we ever end up in the black hole?

Since we are spiraling around the black whole will we spiral into the black hole?
2
votes
3answers
216 views

First night on a telescope questions

So I recently got into astronomy and I am using my fathers old Meade EQ1-B reflector telescope. This is my first night using it and I have come across a few questions. To begin, the telescope was left ...
1
vote
2answers
33 views

How are East and West defined on other bodies of our solar system?

I noticed that East and West appear swapped on maps of the Sun, even though the Sun rotates around its polar axis in the same sense as Earth. See for example below Sun disk with a Venus transit ...
2
votes
1answer
64 views

What is the bluest narrow band filter mounted on ground based telescopes?

If we want to check a QSO's lyman alpha narrow band image, could a ground based telescope do that? I mean under the circumstance that its lyman alpha shifts to 3300A.
5
votes
1answer
88 views

Best telescope for the viewing of Nebulae, Stars and Planets

So, I am a 15 year old interested into astronomy. My father used to have a reflector telescope, but was never so serious about it that he could recommend me a good telescope. I am looking to buy a ...
5
votes
1answer
48 views

What was the age of the universe when the average density was one atmosphere?

How long did it take after the Big Bang for the average density of the universe to reach one Earth atmosphere at sea level? How about the density of water? Is there a chart of densities that relate to ...
2
votes
1answer
49 views

Stellar mass of galaxies

Given the magnitudes (in the i-band) of certain galaxies, I would like to calculate their stellar mass (in terms of solar masses). So far, I have calculated their absolute magnitudes and gotten to ...
1
vote
1answer
26 views

Assumption of our universe being the surface of a 4-D sphere in order to describe relative uniformity in the cosmic microwave background?

It seems as if this is necessary to assume in order for the CMB to make an sense. Otherwise, an instantaneous infinite Euclidean space model would work. The issue is, with any visualization of the Big ...
3
votes
1answer
66 views

Our universe the surface of a 4-dimensional sphere?

The cosmic microwave background that we observe uniformly around us is usually explained by assuming that our universe is the surface of a four dimensional sphere. That way the uniformity makes sense ...
4
votes
1answer
55 views

How did Copernicus get the idea of heliocentric model?

The heliocentric model marked the beginning of modern astronomy. But what were the reasons which led Copernicus to think that the earth orbited the sun. I've read that his model was based on ...
6
votes
2answers
104 views

Is there any difference between parallel universes and multiverse?

Nowadays we come across with these two terms - parallel universes and multiverse. I wonder if this is the same thing or its two entirely different principles because the names are a bit confusing to ...
2
votes
1answer
55 views

Inability of Hubble to clearly resolve nearby celestial objects

The Hubble space telescope performs incredibly detailed and stunning imaging of celestial bodies that are many, many light years away, and yet when it attempts to image objects within our own Solar ...
3
votes
4answers
228 views

Why don't we feel the speed of earth moving

When we move our vehicle, we "feel" the speed of it. However, when stationary, we still are moving,but moving by quiet a speed. We know that earth moves with X ...
0
votes
1answer
15 views

First meteor(s) of Lyrid meteor shower?

So I am a newcomer to Astronomy - only aged 15 - and am currently looking upon the sky in hopes of witnessing several meteors. This is my first time ever - maybe - seeing them. I just went inside for ...
2
votes
1answer
64 views

Conundrum involving distance to object, universal expansion, age of universe, etc

I was recently reading about a galaxy or quasar (not sure which, so lets just say quasar) where the estimated distance to this thing was some very significant fraction of the age of the universe. ...
8
votes
5answers
380 views

Why don't we have 2 Summers and 2 Winters?

Due to Earth's elliptical orbit, its distance from Sun varies by almost 5 million Kilometers (147 million Kilometers at closest point & 152 million Kilometers at farthest point, i.e. almost 3% of ...

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