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7
votes
4answers
6k views

Can we compress any object to create black Holes?

In general, when a star runs out of nuclear fuel, gravity gets the upper hand and the material in the core is compressed even further and creates black holes. I am clear till here. Now the question ...
12
votes
1answer
789 views

Is it possible to see Callisto with the naked eye when it's at its greatest elongation from Jupiter?

A quick search shows that Callisto has an apparent magntidue of 5.65, which would make it easily visible under relatively dark skies. Being the farthest Galilean moon, does it ever get far away from ...
8
votes
2answers
3k views

Has the conjunction between Venus, Jupiter, and Regulus only occurred twice in 2,000 years?

I recently heard the claim that mid-July, the "Star of Bethlehem" formed for the first time in 2,000 years, where the Star of Bethlehem is a three-way conjunction between Venus, Jupiter, and Regulus. ...
1
vote
1answer
83 views

Number of actuators in adaptive optics

It is well known that diffraction resolution of a telescope depends on the exterior radius of aperture: One can, for instance, use just a narrow outer ring of a parabolic mirror and the resolution ...
2
votes
1answer
86 views

Has a near earth object in heliocentric orbit ever been bright enough to be visible to the unaided eye?

The question Can we see asteroid 1998 OR2 with unaided eye? got me thinking. Space.com's Vesta: Facts About the Brightest Asteroid says: Vesta is the second most massive body in the asteroid belt, ...
11
votes
6answers
6k 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 ...
3
votes
3answers
137 views

Is it ever possible to see Earth's shadow on other planets?

Is it ever possible to see Earth's shadow on other planets? How would the shadow present, and what would be the magnification, equipment, or other conditions necessary to see it? Is there any way of ...
32
votes
4answers
3k views

Do moons have moons?

Have we discovered any natural satellites of natural satellites of planets or dwarf planets? Even very small, or relatively short-lived - e.g. ringlets around Saturn's moons, some meteorites orbiting ...
3
votes
0answers
42 views

Focusing issues

I have an 8 inch Skywatcher scope. I have collimated it with a laser collimator but when I tried to study the moon I got just a bright ball and on stars I could see nothing. My lens are a super 10 mm, ...
15
votes
2answers
956 views

Are there neutron stars whose magnetic axis and rotating axis are the same, and if so what will happen?

I know that there's probably a higher chance of having a neutron star that has its magnetic axis inclined to the rotational axis rather than having it perfectly aligned. If they are not aligned, the ...
16
votes
3answers
2k views

What is the probability of seeing a neutron star as a pulsar?

Pulsars are neutron stars that emit a beam of electromagnetic radiation that is not aligned with its rotation axis. If the Earth passes through that beam of radiation, we see a pulsar. Pulsars are ...
1
vote
0answers
31 views

Determine distance to Moon after diurnal parallax?

So, I want to find the distance to the Moon/any body after performing the correction for diurnal parallax. Unfortunately, the resources I have do not cover how to do this. Is there an easy algorithm ...
1
vote
1answer
36 views

Options for observational astronomy [closed]

For getting into a PhD program for observational astronomy, is physics major and data science minor enough?
5
votes
2answers
4k views

Fate of Jupiter when our sun dies

Five billion years from now, the sun will have grown into a red giant star, more than a hundred times larger than its current size. While this metamorphosis into the giant star will change the solar ...
1
vote
1answer
41 views

Right ascension and sidereal time difference

I've read quite a few articles about this and watched visualisations but I still struggle to get a mental map of how this works I understand that on March 21/22 RA 0 is on my meridian at local noon. ...
3
votes
1answer
77 views

What's so interesting about Coma-type galaxy clusters?

When the dynamical mass of a proto-cluster of galaxies is ~(1-2)x1014 Msolar, the proto-cluster is expected to evolve into a coma-type cluster. In almost every paper I read about the confirmation of ...
2
votes
3answers
68 views

Looking for a Solar System Simulator including the smaller celestial body, for macOS

I am researching for a sci-fi novel that will happen in 2136. For this I would like to know specific positions of "smaller" celestial bodies in our Solar System. An example can be the dwarf planet ...
3
votes
1answer
61 views

statistical techniques for estimating distribution of mass

I occasionally hear claims along the line of ' the mass of the universe is not uniformly distributed but actually is concentrated along a ' line, or some other lower dimensional manifold & I ...
4
votes
1answer
1k views

What's the rationale behind the false colours in solar observation photographs?

Images from SOHO, SDO and other sun observatories are often coloured differently for different wavelengths or temperatures: http://www.nasa.gov/mission_pages/sunearth/science/Sun-Wavelength-Chart....
1
vote
0answers
31 views

How energetic was the March 1989 geomagnetic storm?

In the March 1989 geomagnetic storm, how much energy was transferred to Earth's magnetosphere? Most of the articles I find talk about initial solar flare energy, but I have no reason to assume all of ...
6
votes
2answers
297 views

Can you create a black hole using kinetic energy?

Imagine you have a particle accelerator that you can crank up to arbitrarily high energies. Because of General Relativity, the particles get heavier and heavier as you dump more energy into them. ...
2
votes
0answers
52 views

Dozens of Oblong Green Objects in Google Sky

In reviewing Google Sky today for the first time, zoomed in at the southern end of the Aquarius constellation, there's dozens of oblong objects, many of which are green. Considering their general ...
1
vote
1answer
67 views

Is the object a pulsar

We have a star having 1.8 solar mass. Justify any four means (measurable/ observed properties) by which you can identify that the object is a Pulsar and not a white dwarf or a Black Hole. So one ...
1
vote
1answer
35 views

Light levels on other celestial bodies

What I'm trying to achieve For a series of realistic renders I am currently working on I am trying to calculate the light level on different celestial bodies, in terms of the luminous flux (in lumens)...
14
votes
2answers
2k views

During solar eclipses on Jupiter, can the moon(s)' shadow(s) on the surface be seen from Earth with a telescope?

All of the Galilean moons are large and close enough to Jupiter that they can completely eclipse the sun and allow a solar eclipse to happen. My question is can an observer from Earth, see the moon(s)...
3
votes
3answers
481 views

Can I learn astrophysics and astronomy with my basic math?

I want to learn astrophysics and astronomy, I'm very interested in it because there are many questions that popped up in my head, and really curious about things, but I'm afraid of a little bit on ...
6
votes
4answers
4k views

What are the most popular computer programming languages in observational astronomy?

I would like to work in the field of observational astronomy (not so much theoretical astronomy). I currently know two computer programming languages: C# and MATLAB. I have read that computer ...
-1
votes
3answers
84 views

What would happen to the Earth if the orbit of another planet in the Solar System was disrupted by a cataclysmic collision with a large body?

There's plenty of speculation about what would happen if a large asteroid collided with the Earth itself, but less about the effect on Earth of a large asteroid or even a moon or minor planet ...
0
votes
1answer
54 views

Simple definition of Bondi Radius

Can anyone help me by defining what is exactly Bondi Radius? I have searched far and wide but the results are very complicated and so far I have only rough idea of it but I just cant explain it very ...
28
votes
1answer
3k views

Why don’t supergiants at least start to fuse nickel into even heavier elements before going supernova?

The last primary fusion process to take place in extremely massive stars is silicon burning, where the 28Si produced by oxygen burning is exothermically fused with alpha particle after alpha particle ...
1
vote
0answers
77 views

Why are helium resonance lines called “resonance lines”?

Examples of the use of the term: Formation of the helium extreme-UV resonance lines On the Formation of the Resonance Lines of Helium in the Sun (unpaywalled) Formation of the helium EUV resonance ...
1
vote
2answers
93 views

What could be the name of a huge asteroid I watched some years ago?

Some years ago I was with my family in Venezuela. I'm not sure about the date/hour, but probably it was somewhat around 2007 in the afternoon. We were talking when one of us saw a huge meteor moving "...
6
votes
3answers
17k views

When we see the Sun, do we actually see its past?

The Sun's rays hit our eyes around 8 minutes after they are emitted from the Sun. Does this mean that the Sun that we see is always the Sun as it was some 8 minutes before? I strongly think this must ...
4
votes
4answers
509 views

Photon Paradox?

Imagine a photon reaching the Hubble Space Telescope today had originally been emitted from a star in the early universe 13 billion years ago. Einstein’s Special Relativity tells us, traveling at the ...
2
votes
1answer
111 views

How do we measure the brightness of the stars?

How do scientists measure the brightness of so distant stars?
2
votes
1answer
69 views

Which telescope would be better with a DSLR?

I'm interested in astrophotography and since I haven't left my home in six weeks, my interest in photographing the skies has been growing. I'm on a tight budget and I've found these two options: A ...
1
vote
1answer
75 views

How many stars are there max and average per galaxy?

What is the range of the number of stars possible in a galaxy? What is the rough average? Googling leads to vague answers, things like "billions upon billions". But what is a more pinpointed set of ...
3
votes
1answer
154 views

Whose name is Fleming 1 nebula bearing?

Fleming 1 is an unusual planetary nebula situated in the Centaurus constellation. Yet it is not clear after who it was named
2
votes
2answers
3k views

Calculating star radius from temperature and absolute magnitude - what am I missing?

In an attempt to visualise nearby stars, I've tried to get the star radius (measured in solar radii) using the equation provided on the following site: http://cas.sdss.org/dr4/en/proj/advanced/hr/...
3
votes
1answer
60 views

How accurate should sun\moon ephemeris be for calculating eclipses?

I am writing a program to simulate eclipses for about -2000 to 6000. My question is, how accurate does my ephemeris for the sun and moon have to be to get a decent accuracy for eclipses? I currently ...
0
votes
0answers
11 views

Radial velocity data in ALADIN or TOPCAT for Binary Systems

I just installed both, Aladin and Topcat VO tools. I want to know how to search for: HD 226868 and A0620-00 radial velocity data or photometric curves to derive the hidden black hole mass in those ...
0
votes
2answers
62 views

How to create 3D animation of particles position vs time in python?

I am trying to make a 3-D animation of stars' position vs time. I have the information of the stars' x, y and z co-ordinates over time. I was looking at the example of Matplotlib and did understood ...
1
vote
0answers
30 views

possible star train [duplicate]

Over Pennsylvania cloudy night cleared long enough to star gaze, At first I thought shooting star but they kept going in an almost perfect row. Monday Apr 27, approx. 8:30pm. about 15 or more white ...
1
vote
0answers
34 views

How common is it for large objects (few kilometers wide) in a young protoplanetary disk or debris disk to collide with one another?

If enough time has passed for gravitational forces to allow the formation of planetesimals(proto-planets) in orbit around the proto-star, how likely is it that two of them would collide with one ...
2
votes
1answer
41 views

Determining moonset time from Nautical Almanac

I have recently learnt to determine moonrise and moonset times using the Nautical Almanac, as part of my maritime navigation course. I have a query regarding the determination of moonset times. I will ...
-1
votes
2answers
44 views

Objects falling in a black hole radiate their mass?

An object reaching the event horizon has almost infinite kinetic energy. When the total energy of the object surpasses the breaking energy of the electroweak field , the Higgs mechanism would stop ...
2
votes
1answer
41 views

Orphaned star systems and intergalactic travel (in fictional context)

Context: I'm looking for some authority on a particular idea that I brought up in regards to a new update brought out for a space travel sim game, Elite Dangerous The vessels in that game can travel ...
0
votes
0answers
34 views

What was up with the lights in the sky tonight? [duplicate]

I and my boyfriend where looking up in the sky tonight around 8:30 am. We noticed about 17 or more things, that looked like stars. They was perfectly spaced, and just vanished they was heading east. ...
5
votes
2answers
91 views

How do we measure the age of the universe?

As mentioned in wiki/Age_of_the_universe, The current measurement of the age of the universe is around 13.8 billion years (as of 2015) – 13.799±0.021 billion years When my friend who is not from ...
11
votes
2answers
1k views

How complicated is the heating of meteors?

When any gas, including our atmosphere, is compressed, it's temperature rises. When a meteor is falling through the atmosphere, it is compressing the air below it. Because this makes the air hotter ...

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