# All Questions

58 views

### Measuring star distance by parallax using a small telescope

I was wondering if it's possible to measure star distance using parallax at home with a small telescope (Something like a 3-inch reflector)? Or is this not really practical?
56 views

### What is the distribution of organic compounds in the Milky Way Galaxy?

I imagine the answer is unknown for the entire galaxy, but I'd appreciate a notion of the scales and locations of regions where astronomers have ventured at least a guess as to the distribution of ...
30 views

### Transform pixel coordinates (in FITS file) to equatorial

Say I have a FITS file with an observed field of stars, each one with x,y coordinates given in pixels. Assume the image is aligned so that the x axis is the right ascension, and the y axis the ...
213 views

### Can we find rocks from Venus or Mercury on Earth?

As we know, we can find rocks from Mars on Earth, how about Venus and Mercury? Is that not found yet? Or it is impossible to find them because they are closer to the sun and derbis won't go far away ...
116 views

### Why is space and time spoken of as one thing

I've never understood why it's spacetime and not space and time. In other words why aren't space and time spoken of as two different things. Can someone explain to me why this is
83 views

### Create a signal to noise map from heatmap

Recently, I obtained my heatmap from a sky survey. But now, I'm trying to get a signal to noise map from my heatmap. My heatmap looks like : My colour bar indicates the number of stars per pixel ...
120 views

### Does conservation of energy make black holes impossible?

I was musing today about black holes, and came across what seems to be a contradictory fact about black holes. If any matter were to actually fall into a black hole, it seems like it would need to ...
6k views

### How does gravity really work

I am only 12 years old and I'm constantly wondering and trying understand how gravity really works. On YouTube everyone always talks about objects warping space time around themselves and uses the ...
44 views

### Equation of the Center constant factor

This questions concerns the longitudinal aspect of the Equation of Time, also called the Equation of the Center. In some sources the equation looks like the following: $\nu - M = 2\varepsilon \sin M$ ...
54 views

### How can a low-mass star increase its mass to 1.4 Msun? [closed]

In my astronomy class I learned that a only low-mass stars (< 0.5 Msun) will contract, and then become degenerate, until it is a white dwarf. However, we also learned about the Chandrasekhar limit, ...
129 views

### When Phobos collides with mars (or breaks up), will it have any noticeable effects on Earth?

When Phobos meets its predicted doom in a few 10s of millions of years, whether it breaks up or collides with the surface of Mars, will this change have any noticeable effects (permanent or temporary) ...
52 views

### After the Sun becomes a red giant, will most of the nucleosynthesis still be from proton-proton fusion?

After the Sun becomes a red giant, will it continue to mainly run on the pp-fusion, or some other type of reaction, like the CNO cycle or the triple-alpha process? On that note, do most other stars ...
43 views

### The moon: how to determine its size, speed and distance from earth using a simple telescope?

Assuming I only have a simple telescope, how can I determine the size of the moon, its angular velocity and distance from earth?
191 views

### How far into the future can we go by traveling close to a black hole?

If we sent someone on a path that passed as near as possible to a black hole without getting pulled in, how far into the future would they go due to time dilation? Let's assume the black hole is 5 ...
122 views

### Why are black holes that massive?

Today known most massive star, R136a1 weighs approximately 256 times the mass of our sun, how did supermassive black holes, with a mass of 10 billion times the sun form? I understand, that when a ...
656 views

### Why are there so many seemingly blue-shifted galaxies in deep space

NASA released this image of deep space. The way light shifting vis-a-vis universe expansion is supposed to work is by making the furthest galaxies appear mostly red-shifted. But NASA's image shows ...
37 views

### Latitude and Longitude from Right Ascension and declination angles [duplicate]

Given Declination and Right ascension(RA) of Sun ,How can I calculate the position of sun in terms of Earth's Latitude and Longitude(Or the vector from Centre of Earth to Centre of Sun will pass ...
49 views

### Gravitational Waves and the Big bang

The Ligo website says "Detecting the relic gravitational waves from the Big Bang will allow us to see farther back into the history of the Universe than ever before." I find this puzzling. How can a ...
32 views

### Open access table of visible stars with magnitude, coordinates, and possibly color?

I'm looking for a link to a table of visible stars that is open and available to everyone. It should have magnitude, RA, dec, and possibly some indication of color. This will be used to produce ...
101 views

### Are there any hot jupiters orbiting red dwarfs?

Do we know of any hot jupiters that could be orbiting a red dwarf (or, more probably, orbiting a barycenter between the two)? Is this scenario even physically possible?
108 views

### How is mass curving spacetime?

In the GR Einstein's interpretation was in terms of a deformation of the geometry of the space ending in a curvature of spacetime. I've thought that mass could do this by interacting with other mass ...
33 views

### 3D array in FITS data

I am an amateur astronomer currently working on Spitzer telescope dataset with python (astropy and aplpy). From the examples in astropy's website, I understood that the FITS data is a way to represent ...
18 views

### Infrared Astronomy for non transiting objects?

I understand how infrared spectroscopy works for determining molecules in the atmosphere of a transiting object (like Venus from Earth). But how does this work for objects that don't pass between us ...
42 views

### How to find maximum and minimum right acsension and declination based on the telescope's location?

If I am to apply at a telescope for viewing objects, how to determine (easily) what is the minimum and maximum possible RA and DEC visible from that telescope during that time of the year. For eg, ...
4k views

### Why can't moon light (reflected sun light) turn the sky blue?

Does turning the colour of the sky blue need more luminous light? Does it depend on luminosity or some other factors are also responsible for this phenomenon? Why can't the moon light turn the sky ...
128 views

### Can life survive on the equator of cooled and fast rotating white dwarf or neutron star?

As I know, some stars produces carbon, nitrogen and oxygen when they are old and become white dwarfs or neutron stars. And even their surface gravity is strong, it may rotate very fast so that the ...
81 views

### Celestial impacts

Have we ever observed, or better yet, recorded, an impact from a comet/meteorite/fragment/etc on another celestial body? For example, in all its time orbiting Mars, has the MRO observed anything ...
186 views

### Is there a limit to the size of a black hole?

The mass of a star is limited to about a couple of hundred solar masses. The fusion rate scales strongly with density (which is why the most massive stars have extremely short lifetimes) so if a star ...
65 views

### Could dark matter assist with star formation?

This is related to the question: "Can dark matter decrease the Jeans length?" If dark matter assists in any way with star formation, shouldn't it be detectable by precisely measuring velocities in ...
67 views

### Given a collection of pixels, how to deduce the flux from them?

I've obtained the coordinates of brightest pixels from different images (.fits files) using Python. I want to get the flux of each pixel. How do I go about finding out the flux?
4k views

### Why doesn't the moon twinkle?

Stars twinkle because their light has to squeeze through several different layers of the Earth's atmosphere. So why doesn't the moon twinkle as well?
71 views

### Why aren't planet orbits circular? [duplicate]

Please forgive the simplicity of my question. I have only had basic science courses. Common sense seems to indicate that planetary orbits should be very close to circular, any perturbations having ...
66 views

### How can we tell that the sun is moving with theories such as the theory of relativity?

In a nutshell, the theory of relativity says that we cannot know that the ether is moving because if we were on the sun, the earth would seem to be moving and visa-versa. Apparently, we can't find ...
34 views

### Notifier about visible ISS passes and/or Iridium flares for Ubuntu PC

I am trying to find application that would be capable of notifying me about visible ISS pases for specified location and/or visible Iridium flares for specified location. This software must be ...
70 views

### Telescope choice

Which one is better? Features: 1)Magnification: 18x - 90x Eyepiece Diameter: 5mm (18x), 10mm (60x) Objective Diameter: 50mm Focal Length: 36cm Tripod Height: 38cm Main tube Color: Silver Net ...
81 views

### What star system/Galaxy did LIGO observe the gravity wave?

Are there any coordinates for the Black Hole system, or galaxy for which the LIGO observations, observed the gravity wave? Any coordinates of the black hole system for which the gravity wave signal ...
483 views

### Which of Jupiter's moons did I most likely see?

I was gazing through my binoculars at Jupiter last night and noticed 3 (maybe 4) tiny dots in line with it. A first I thought they might have been background stars but quickly realised their colour ...
29 views

### How to calculate B-V colour index value percentage difference

I need to calculate a percentage difference of a B-V colour index between its estimated and actual value. So I tried doing this by difference between values/actual value x 100. However as B-V values ...
49 views

### Why do we need the “mean” in mean free path?

I was introduced to mean free path in my astro physics class, and the professor posts a question for us to ponder: "Why do we need the "mean" in mean free path?" This further makes me to wonder what ...
1k views

### Why do comets appear to have a continuous supply of dust?

Comets orbiting the sun have a tail that points away from the Sun, due to the solar wind. (Strictly speaking, a comet can have both a type I tail - ion tail, and a type II tail - a dust tail. This ...
30 views

### Moon SHAPE calculator

I have seen a lot of information about moon phase calculation, but need an accurate moon shape calculator/algorithm given the observer's position and time. This implies that the illuminated portion ...
64 views

### Is dark matter influenced by gravity of baryonic matter?

As far as I know galaxies and clusters form along so-called "galactic filaments" which are influenced by a dark matter web that organises them in to this position in the universe. So it looks like ...
167 views

### How do we know galaxy GN-z11 is as far away as it is?

The news media recently reported that galaxy GN-z11, formed just 400 million years after the big bang, is much further away than originally thought at perhaps 13.2 billion light years. They say, ...
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### K-Pg asteroid impact

Is it possible to determine what daytime the Chicxulub impactor striked the Earth 66 mya? Was it day or night, what was the current phase of the Moon etc.? Can sediments, rhytmites or something else ...
22 views

### Convergence of galaxies [duplicate]

What would happen to Earth and other planets after about millions of years at the time of convergence of milky way galaxy with andromeda galaxy? (Supposing the planets and the sun are still there and ...
41 views

### Infrared Region Telescopes

Why do we need to build telescopes that can view in the infrared? What exactly do we need to see in the infrared region? I know this seems like a really broad question but I'm just curious about it.
98 views

### Color of planets

I am developing an astronomy software and need to know the color of each planet in the Solar System, when observed with the naked eye. I cannot find that information after googling for a while. Is ...
71 views

### How do solar winds affect the atmospheric composition and density of planets?

Here is a bit of a newbie question, if you please. The sun is constantly ejecting small particles via solar winds that come into contact with planets and other objects in our solar system. Do these ...