6
votes
2answers
215 views

Confirm: We can only notice planets if their orbit passes in front of their star and our view

If we can tell a planet exists by the dimming of the brightness of a star when it passes in front of our view of the star does that mean we cannot see a planet if it does not cross in front of our ...
5
votes
1answer
92 views

What are the possible solutions to the Red Supergiant problem?

I have recently come across this so called "Red Supergiant problem" in the literature, a phrase that was coined by Stephen Smartt in 2009 in reference to why red supergiants with masses ∼16-30M⊙ have ...
8
votes
2answers
168 views

What's the distinction between “planetary formation mechanisms” and “gravitational collapse”?

As I was curious about the exact identical comment to my title here: http://astronomy.stackexchange.com/a/16135/10102 And as it seems no one asked it yet, I'm simply interested in the difference of ...
7
votes
4answers
194 views

How did the Earth come to be in orbit around the sun?

I'm not sure if this post should be in the physics subject forum, but this seems to fit here too. I have been reading a book about chemistry and how the universe came to be with the theory of stars ...
4
votes
2answers
35 views

Capability of observing transits with terrestrial telescopes of various sizes?

I have access to my university's telescope, Dearborn Observatory, an 18.5 inch refractor on the shore of Lake Michigan, just north of Chicago (yes, it's an atrocious location, but the telescope still ...
10
votes
1answer
2k views

Why can't our Sun be a binary with Jupiter as a T or Y dwarf?

I just learned about Brown Dwarfs, they are "failed" stars, they narrowly missed the stellar mass mark. I learned that Y Dwarfs have temperature as low as 80 Fahrenheit (The first one found by WISE ...
3
votes
3answers
87 views

Question related to Sun rise and Sun set times

I am not sure whether this question is right or not so bear with me. I understand 'Sun rise' and 'Sun set' is caused by the Earth's rotation. I read that 'Sun light' takes around 8 minutes to reach ...
0
votes
0answers
16 views

How long do hot X-ray sources last?

Some X-ray sources in nebulae are caused by hot materials in the millions of degrees that formed in supernovae. What's the cooling rate of this stuff? How long does it stay this hot? I would expect ...
3
votes
1answer
64 views

What exactly is this VLA radio image of Jupiter showing?

This VLA image is beautiful, and instructive, but I don't understand it fully. This version is from an article in Gizmodo where the credit reads: A radio image of Jupiter captured by the Very ...
6
votes
1answer
159 views

Why does lithium fuse at lower temperatures than hydrogen?

This is a basic question, but it's been bugging me. In the Wikipedia article for lithium burning, it states that: Stars, which by definition must achieve the high temperature (2.5 × 10^6 K) ...
1
vote
2answers
70 views

Was the radiant of the Perseid meteor shower ever near Vega thousands of years ago?

The ancient Chinese story of the Weaver Girl (Altair) and the Cowherd (Vega) tell of starcrossed lovers who are only allowed to meet once a year on the 7th day of the 7th (Chinese) lunar month, ...
20
votes
1answer
1k views

Why is there a gap in this image of supernova discoveries?

I came across this gif showing supernova discoveries from the late 19th century to 2010. Here's the data in 2010: Notice that there's a prominent region shaped like an inverted U in which there are ...
3
votes
3answers
78 views

Can't we see all of the Milky Way's supernovae with the naked eye?

I found this on the Wikipedia page on supernovae: The total supernova rate in our galaxy is estimated to be about 4.6 per century, or one every 22 years, although we haven't actually observed one ...
1
vote
1answer
94 views

If the universe keeps expanding, can we travel to the edge of the universe? [duplicate]

If the universe keeps expanding, is it possible to travel to the edge of the universe?
1
vote
1answer
60 views

What causes celestial bodies to move like they do from Earth's surface?

As you probably know, the planets have pretty predictable orbits around the sun but what exactly causes the complex movement of celestial bodies in the sky from Earth's surface? Mars is an excellent ...
0
votes
1answer
32 views

Can a meteor shower happen simultaneously all around the planet?

In the original book, the classic 1962 movie and the modern 2001 re-make for TV. The store "The day of the Triffits" depicts a meteor shower that happen all around the Earth at the same time, and ...
0
votes
1answer
80 views

Is the material that could have formed a “Super-earth” divided among the four terrestrial planets

I know "super-earths" are quite common in other planetary systems, but there are none in the Solar System. Is it due to the material that could have created a single large super-earth being used to ...
0
votes
0answers
46 views

Peculiar orbit of circumbinary planet

I've created a Mathematica notebook file which should theoretically allow one to simulate any n amount of bodies. Whilst looking at a three-mass system where $m_1=m_2=2000m_3$, I noticed some peculiar ...
0
votes
2answers
35 views

SDSS Image FITS files have negative values. What do these negative values mean?

I am new to using SDSS image files and have noticed that some of the values in the FITS file are negative. Can somebody explain to me what these values actually mean?
7
votes
5answers
204 views

How cold is interstellar space?

The vastness of space brings me a sense of chilliness even though I have never experienced it, although I wish to. Just how cold is interstellar space (on average)? How is this even measured? I mean ...
1
vote
1answer
124 views

How could universe inflate itself out of the very dense and curved early spacetime? Could it happen in a black hole too?

Wasn't spacetime as much curved as a black hole directly after Big Bang, because mass was so densly packed? Wasn't everything like an event horizon and how could things expand across it? Could ...
1
vote
2answers
46 views

Was time different before the great inflation?

In time different during the first second after Big Bang than it is now? Inflation had a dramatic effect on space, and spacetime is one thing. Was the properties of time affected too? Curved spacetime ...
5
votes
2answers
458 views

Are there any common characteristics of habitable planets?

Recently, over a thousand exoplanets were confirmed in one huge sweep which is a huge achievement and in the mix a dozen or so possibly habitable planets were confirmed as well. This made me wonder, ...
0
votes
2answers
24 views

Which elements are an indication of habitable exoplanets?

Using spectroscopy the chemical composition of exoplanets atmosphere is determined. As a scientist, what spectral lines would you look for? Which elements are relevant in pursue of a second earth?
1
vote
3answers
113 views

How large (that is, radius) could a planet be?

I know that normal planets don't get any larger than Jupiter (or 2 Jupiter radii if hot), as adding more gas just increases density, not radius, until you reach the point of being a brown dwarf star. ...
7
votes
6answers
2k views

How do I prevent or reduce shake when observing with binoculars?

I have some 16 x 50 binoculars that my parents bought me years ago. Recently I have tried to do some basic lunar and planetary observations with them but I am seriously struggling with shaking. This ...
0
votes
2answers
86 views

Is it possible to have a star orbiting around a brown dwarf?

I know a single star is almost surely more massive than a single brown dwarf, but consider a case: a very small star is orbiting a very massive brown dwarf which has a very massive moon, such that the ...
1
vote
1answer
87 views

What would happen if an astronaut orbiting Earth was exposed to radiation? [closed]

I know that astronauts are constantly being protected from radiation from the sun and the cosmos. They are normally very safe from the harmful effects of radiation but what if their protection wasn't ...
0
votes
0answers
8 views

IDL (particularly GBTIDL) velocity axis explanation?

I have been working with GBTIDL (the Green Bank Telescope version of IDL I suppose) to look at some spectra, and in addition to having the x-axis be frequency or wavelength, you can also have it in ...
1
vote
1answer
30 views

What does the filter name I+z' mean

On the TRAPPIST telescope, the filter wheels are described to have a filter with the following description: NIR Luminance I+z' (>700nm) After a bit of googling, I wasn't able to find what the ...
4
votes
4answers
2k views

Can a comet orbit a planet?

Given that moons commonly orbit planets, why do we never encounter a comet orbiting a planet? What would happen (exactly, in detail) if a large one did settle into a stable orbit around the Earth? ...
6
votes
2answers
144 views

Why is the core of a gas giant supported by electron degeneracy pressure instead of nuclear fusion?

After a Sun-sized protostar forms, its core will become denser over time due to radiation. The core eventually gets dense and hot enough for hydrogen fusion to take place. In the late phases of the ...
3
votes
2answers
178 views

Can I leave a planet without achieving escape velocity?

I know that if you exceed orbital velocity, you will never fall-back to the planet. My question is not about orbits. It's about brute-force propulsion to achieve altitude. I'm using an ...
1
vote
1answer
46 views

How do astronomers detect gases that are in the atmosphere of exoplanets?

Exoplanets are planets that are located outside our solar system - whether that be orbiting a star or drifting past one. Now, the closest star to us is Alpha Centauri which is just over four light-...
0
votes
0answers
9 views

Does the dust around SMBH's protect habitable planets from jets?

The supermassive black hole in the Milky Way is covered by dust as seen from here. Is it common that SMBH's are covered in dust in their galactic disks? Would that dust absorb and disperse a jet from ...
11
votes
2answers
2k views

Could the 9th planet be virtual?

Astronomers recently claim that there is evidence for a 9th planet. As far as I understood it, this is mainly based on coinciding orbital parameters of a few Kuiper belt objects. Could the 9th planet ...
0
votes
0answers
18 views

How to calculate the total flux of a source from a fits file?

My fits file is a spire 250micron image that has data units of Jy/beam . I injected a source into it with a peak intensity 20Jy and fwhm(3,3). How can I calculate the total flux of the source? Please ...
0
votes
2answers
43 views

Warm and Hot dark matter density profiles

For cold dark matter, density profiles are well known and easy to find information about - eg. NFW, Burkert, Einasto, and others. But for some reason I couldn't find explicit expressions for the ...
8
votes
2answers
111 views

Why do we use FITS format for scientific images especially in astronomy? How is it different from formats such as JPEG, PNG etc?

I am new to astronomy and I found that the telescopic dataset can be stored in the FITS format instead of JPEG. Why do we have a special image format just for scientific images?
1
vote
2answers
90 views

Which stars do I have to use to join with a line to draw constellation?

I continue working on a planetarium software and I want to draw the lines that the draw the constellation's figure: Is there a catalogue or something similar with the stars which are the vertex of ...
1
vote
2answers
38 views

R.A. and DEC. for Constellation area vertices

I'm developing a planetarium software and I need the R.A. and DEC that represents every constellation area in the sky. I think I only need R.A. and DEC for each vertex. Where can I find it? I'm ...
1
vote
1answer
64 views

How large could gravitational waves get and what effect could they have on us?

The waves detected by LIGO were basically subatomic distortions of space-time. Could there be much greater distortions closer to a source. Would they become perceptible to a human in any way and what ...
0
votes
1answer
150 views

LIGO gravitational wave chirp signal frequency

This question is about the LIGO gravitational wave signals' frequency. The signals start from about 35 Hz to peak at about 250 Hz, giving evidence of gravitational waves. The question is about the ...
1
vote
2answers
55 views

“Supernova” is the explosion or the resulting celestial body? Is it incorrect to call the explosion “supernova”?

Sorry for such a newbie question. I searched and read multiples sources about supernova but I'm not completely sure if what is called "supernova" is the explosion, the resulting celestial body or the ...
0
votes
1answer
58 views

Calculating azimuth from equatorial coordinates

I try to get the azimuth of an object from its equatorial coordinates using this formula: $a = \arctan2(\sin(θ - α), \sin φ * \cos(θ - α) - \cos φ * \tan δ)$ Where φ = geographic latitude of the ...
0
votes
0answers
39 views

How to orientate a telescope using an accelerometer and magnetometer?

For a project with my astronomy professor, we are hooking up an array of 4 smaller telescopes to observe objects in space together. To do this, we wanted to put an accelerometer and magnetometer on ...
0
votes
0answers
42 views

Converting ecliptical to equatorial coordinates

When looking for a formula to convert polar ecliptic geocentric coordinates of an object to equatorial coordinates I find various sources that give these formulae (like Wikipedia): Declination $δ = \...
3
votes
1answer
60 views

Will the E-ELT use Adaptive Optics at visible wavelengths?

In this recent BBC article I read that the European Extremely Large Telescope or E-ELT is in final design and is planned to be on line by 2024, and that (of course) it will rely heavily on adaptive ...
6
votes
1answer
87 views

What is a quaternary mirror and why does the E-ELT need one?

In this recent BBC article I read the one-sentence paragraph: "Development on the mirrors - in particular, a very complex quaternary mirror - continues apace." and became interested in the ...
6
votes
2answers
113 views

Difference in energy released in stellar mass black hole merger and supermassive black hole merger

Super massive black holes are usually millions of times more massive than stellar mass black holes. I have read on SE and over internet that 3M☉ worth of energy is released in black hole mergers (not ...

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