9
votes
1answer
93 views

Which came first: black holes or galaxies?

In other terms, did galaxies grow around black holes at their center?
6
votes
1answer
133 views

In what timeframe is W26 expected to go supernova?

All the news-articles say that it is expected to "eventually" explode. Which doesn't really tell me much. When is "eventually"? Also, considering this is the largest star in the known universe and 16k ...
6
votes
0answers
100 views

Determining effect of small variable force on planetary perihelion precession

Is there an analytical technique for determining the effect of a small variable transverse acceleration upon the rate of precession of a planet orbitting around the Sun according to Newtonian gravity ...
9
votes
1answer
73 views

How is it known that Callisto has no core?

My Astronomy book claims that scientists have discovered that Callisto, a moon of Jupiter, has no hot inner core. In fact, it says, Callisto has a core much like the nucleus of a comet. Is this still ...
5
votes
1answer
221 views

Why does Titan's atmosphere not start to burn?

If Titan has a methane atmosphere and seas of methane, then why doesn't some meteoroid / chemical reaction ignite and blow the whole thing?
15
votes
2answers
332 views

Why is our solar system “tipped” about 63° with respect to the plane of our galaxy?

Our own solar system is "tipped" by about 63 degrees with respect to the plane of the galaxy. Has it ever been researched or is there any scientific theory which could explain the reason why our solar ...
16
votes
1answer
159 views

What causes a star to become a pulsar?

What processes does a star undergo to become a pulsar? Does it take a very specific star with a certain set of qualities such as "Just the right mass, diameter, and composition," or is it a freak ...
7
votes
1answer
72 views

What is the largest recorded solar flare?

For the purposes of this question I would interpret the word "recorded" as loosely as possible meaning that historic records such as ice cores or tree rings would count. Also what effect did such a ...
7
votes
1answer
274 views

How does moonrise/moonset azimuth vary with time?

In my tenacious attempts to observe moonrise (surprisingly difficult in a poor weather heavily urbanized hilly area with frequent bad smog, with busy work schedule and a bicycle) I was frequently ...
9
votes
2answers
223 views

Do other planets in our solar system experience eclipses or is this unique to Earth?

Here on Earth we get to experience lunar and solar eclipses. Is this pure coincidence that everything happens to line up? Do other planets in the solar system experience this phenomenon or is this ...
6
votes
1answer
91 views

What is the mass of hotspots in the Cosmic Microwave Background radiation?

A lot of pop science articles (for example, this Space.com article) discuss the cold spots on the WMAP data of Cosmic Microwave Background (CMB) radiation, but have any studies been done on the large ...
1
vote
0answers
41 views

Is the moon rotation at complete standstill? [duplicate]

Moon always faces Earth with one side, its spin period equal its orbital period - this is what we learn at school. But I know Nature rarely operates in absolutes. I'd find it hard to believe Moon ...
5
votes
1answer
44 views

Who or what will the Arecibo message reach?

The Arecibo Message was aimed at the globular star cluster M13, but as far as I read, M13 will move out of the original position and thus not be able to receive it. So, who or what will be able to ...
7
votes
1answer
84 views

Age of the universe

We know that the universe is approximately 13.7 billion years old. What methods did we use to discover this? How sure are we about its accuracy?
5
votes
1answer
107 views

Are Barlow lenses stackable for bright objects?

I'm back to the refractor that I own, and I want to maximize the zoom capacity. I realized today that I own more than one barlow lens, and I was wondering if I could stack them together for looking at ...
7
votes
1answer
38 views

Does the Reflection Method for Looking at the Sun Work For Refractors?

I own a newtonian reflector and occasionally use it (using the reflection method with paper) for looking at the sun. I happen to also own a refractor, but I'm not exactly sure if the reflection method ...
6
votes
1answer
50 views

How does interstellar matter density vary?

Answer to my question partially answers this one, about density of intergalactic matter and matter within galaxy: But it is mostly a hot, ionized void. How void? The density of the intergalactic ...
9
votes
1answer
121 views

How Does a Refractor Telescope Work?

As I understand it, the difference between a reflector and a refractor is that a reflector uses mirrors on the back to reflect the light to the secondary mirror then the secondary mirror reflects the ...
0
votes
1answer
47 views

What do shape of universe mean? [closed]

What shape does a three dimensional universe have ? and how did scientists determined that it is flat and not curved.
8
votes
1answer
132 views

How do we detect if a planet has a liquid core?

In case of Earth, we have many hints about the internal structure of our planet, from what I know, the most important of which is analyzing seismic waves. Do we have any instruments to detect if ...
7
votes
1answer
83 views

What is the Lyman Alpha forest Used For?

The Lyman-alpha forest is an interesting feature found in the spectra of sufficiently distant objects. This series of absorption lines extends over a range of frequencies, and are a result of the ...
7
votes
1answer
70 views

Have we observed any rogue/wandering stars?

Do we know (have we observed and cataloged) any rogue star, being not part of galaxy, but drifting somewhere in inter-galactic space? I know that determining if a star is a part of galaxy or not is a ...
6
votes
1answer
33 views

Long term development of Comets

When an exocomet passes by our Sun in a trajectory that leads it to establish a Solar Orbit what eventually happens to it? In addition to its original inertia and vector being altered what are the ...
3
votes
0answers
39 views

Which are the consequences of Uranus' high rotation axis angle? [closed]

The rotation axis of Uranus is 90 degrees away from vertical, there are some theories about its reason.. But which are the consequences of this? Which are the unique features of Uranus that happened ...
10
votes
1answer
823 views

How can I collimate a dobsonian telescope with a laser collimator?

I've had a dobsonian telescope for a while now, but I've never been able to collimate it. I thought I had it collimated once, but when I looked through it the star didn't look right, it looked kind ...
4
votes
0answers
45 views

What was the greatest spatial extent of the Asteroid Belt prior to the Late Heavy Bombardment?

Reading the article On the asteroid belt’s orbital and size distribution (Gladman et al. 2009), there is an interest point made: asteroids a few kilometers and smaller in size are recent ...
8
votes
2answers
48 views

What azimuth description systems are in use?

For a time, I thought Azimuth is always direction in degrees, 0 for local, geographic north, 90 for east etc. Then, trying to observe moonrise I downloaded an app that gave azimuth in values between ...
9
votes
1answer
208 views

Why has Venus's atmosphere not been stripped away by solar wind?

This answer on Space Exploration to a question about Mars says that one reason Mars has such a thin atmosphere is because it lacks a magnetic field to protect it from the effect of double solar winds. ...
10
votes
1answer
100 views

Were effects of a planetary magnetic field reversal observed on other planets than Earth?

From geological records in rocks and minerals we know that the magnetic field of Earth changed its polarity multiple times in the history. See Geomagnetic reversal. Was a similar process of a ...
5
votes
1answer
41 views

How much oxygen did the Warwick/Cambridge study find in the rocky debris around white dwarf GD 61?

There are several articles out saying that a Warwick/Cambridge study of ultraviolet spectroscopy data from the Cosmic Origins Spectrograph on the Hubble Space Telescope found a large amount of oxygen ...
11
votes
1answer
101 views

Have we ever observed a large meteor hit the Moon?

Since the moon has no atmosphere, its surface has many more meteorite impacts than Earth's does. Image source Have we ever observed a meteor strike the surface of the Moon?
6
votes
1answer
57 views

How do large solar flares compare to flares on other stars?

Solar are violent releases of solar magnetic energy. Other stars are also known to have magnetic fields, in some cases much stronger than the Sun. How do the largest stellar flares compare to the ...
2
votes
0answers
62 views

How can I create tracks of the planet's orbits on my computer? [closed]

I'm wondering if there's any good computer software for tracking the orbits of planets over time. I like to see the orbit's trails against the sky background. I'd prefer something that's free and of ...
12
votes
1answer
130 views

How do/did we figure out that planets move in orbits?

I've learned that planets move in orbits around the Sun, but I really don't know how I would come to this conclusion myself. I've only seen planets in the sky a couple times (knowingly), and I am ...
5
votes
1answer
198 views

What is the standard reference point for measuring speed?

Speed, as we know, doesn't exist without first having a reference point. We then say that the reference point isn't moving at all, and speed is then measured in relation to the reference point. What ...
8
votes
3answers
426 views

Jupiter FM - What are practical and inexpensive ways for the amateur detection of signals from Jupiter, especially of the transit of her moons?

What modifications to a standard AM/FM or shortwave radio are needed in order to be able to detect radio-wave signals emitted from Jupiter? Would it be possible to detect the transit of the major ...
6
votes
1answer
67 views

How can an amateur astronomer verify the position of near Earth objects?

Sometimes, hobby-astronomers use rather professional means to observe the big voids of space. Every now and then (think in months, not days) even I can locate an NEO (near Earth object). Now, I'm ...
14
votes
1answer
168 views

How distances are measured in the Solar System, in the Galaxy, and in the Universe?

Distances in our universe can be calculated in several ways: Stellar Parallax Standard Candles Redshift How are these methods linked, and how they are actually used to calculate distances are ...
10
votes
1answer
142 views

Why did the Comet Shoemaker-Levy-9 fragments cause such large explosions on Jupiter?

In July 1994, the comet Shoemaker-Levy 9 (D/1993 F2) tidally fragmented and these fragments collided into Jupiter, as per the image below. Image source The question is, what mechanisms resulted in ...
4
votes
1answer
57 views

How long would it take for a rogue planet to evaporate in the late stages of the Universe?

I've read once a popular science book, in which the author calculated how long would it take for the most massive black holes to evaporate because of Hawking radiation. He claimed that after that time ...
4
votes
1answer
33 views

Why do X-ray binaries such as GRS-1915 have active and quiet states?

X-ray binaries such as GRS-1915 feature a black hole and a regular star. The x-ray luminosity is likely related to the rate of mass flow into the black hole from the star so when there is a lot of ...
6
votes
2answers
262 views

Are Barlow Lenses Good For Deep Sky Observing?

I'm using a 750mm (focal length) by 150mm (aperture) newtonian reflector and I've been curious about using Barlow lenses on deep sky objects. Some of the astronomers at my local observatory say that ...
7
votes
2answers
51 views

What is the Neupert Effect?

This effect is frequently discussed in the context of solar time series. In particular, it a relationship between soft x-ray (thermal emission) and hard x-ray (nonthermal emission) from the Sun.
10
votes
2answers
227 views

Why does the Earth have a tilt of ~23°?

Is there a reason that the Earth has the tilt that it does (~23°)? How do we know which way is supposed to be 0°? Does this tilt have major consequences on the planet? Has it changed and will it ...
12
votes
3answers
401 views

Should I focus more on Aperture or Focal Length for a telescope?

Let's assume there are three types of telescopes with the following specifications: ...
11
votes
1answer
98 views

Affordable night sky photography

As an amateur with limited budget, I'd be interested in taking photos of the night sky, trying to capture more detail than human eye armed with a lens of comparable parameters to what I have in my ...
11
votes
2answers
177 views

What physical features determine if a planet is a major, minor or dwarf planet?

Like many, when I was growing up, we always were taught, hence always learned that there were 9 planets. However, recently, decisions were made and all of a sudden there were 8 major planets and a ...
5
votes
1answer
61 views

Did the Late Heavy Bombardment Period Happen Because of a Stellar System Collision?

I was thinking about the impending collision between M31 and the milky way galaxy, and I've heard that since a galaxy is mostly space most of the contents of both galaxies would be just fine. Could a ...
12
votes
1answer
92 views

Why is the Sun's atmosphere (the corona) so hot?

The visible surface of the Sun is 6000 degrees Celsius but the gas in the solar corona is at least 1 million degrees. What heats the solar corona?
5
votes
1answer
120 views

Why does squinting make hard-to-see objects clearer?

So I, like most other astronomy enthusiasts, have, at some point, not been able to see something clearly, such as a star, and have had to squint to be able to see it better. When this happens, the ...

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