Community Digest

Top new questions this week:

Why is Venus's atmospheric pressure 75 times that of earth when carbon dioxide is only 1.5 times heavier than air?

Obviously I have forgotten by basic college chemistry. I am getting carbon dioxide at 1.87kg per cubic meter and compared it to nitrogen and oxygen but source says carbon dioxide is 1.5 times heavier ...

planetary-atmosphere venus  
user avatar asked by Sedumjoy Score of 18
user avatar answered by David Hammen Score of 30

Could it be possible to detect planets from stars that went supernova through the resulting nebula shape?

It ocurred me, if a star with at least one planetary companion undergoes a nova or supernova, we shoud expect the debris to be deflected to some degree, on exit. To ilustrate it, first let's take the ...

planet exoplanet supernova nebula stellar-remnants  
user avatar asked by ksousa Score of 14
user avatar answered by ProfRob Score of 23

Adhara ultraviolet magnitude

I see Adhara is cited in many places (for example, here) as being the brightest source of ultraviolet light in the sky. The particular source uses the modifier "extreme", but most other ...

star apparent-magnitude  
user avatar asked by L. Scott Johnson Score of 8
user avatar answered by ProfRob Score of 9

How do I calculate the moment of the solstice?

I'm trying to calculate the moment of the upcoming summer solstice using astropy, and I can't seem to get an answer that matches the accepted values that I see online. I thought that the moment of the ...

observational-astronomy the-sun astropy solstice  
user avatar asked by Roy Smart Score of 7
user avatar answered by Roy Smart Score of 7

Does syzygy mean only three aligned bodies, or at least three aligned bodies?

In the precise and rigorous astronomical use of the word, does the term "syzygy" refer to an astronomical alignment of three and only three bodies? Or, can syzygy be interpreted as an ...

observational-astronomy naming  
user avatar asked by Plane Wryter Score of 3
user avatar answered by Starship is go for launch Score of 4

How (the heck) does an astronomical Celescope work? And how did it get its name?

Here's an exceprt from the recent question The claim may refer to the band labeled U4 in the Celescope Catalog of Ultraviolet Stellar Observations, which refers to a filter with a spectral response ...

observational-astronomy space-telescope naming nomenclature ultra-violet  
user avatar asked by uhoh Score of 3
user avatar answered by GrapefruitIsAwesome Score of 3

How to find zero velocity contours for circular restricted 3-body problem in x-y plane?

(I am having physics background; I am not an astronomer/astrophysicist.) How to solve a single nonlinear algebraic equation in two variables, $x$ and $y$? (I know that - if there are two variables, ...

celestial-mechanics n-body-simulations  
user avatar asked by atom Score of 3
user avatar answered by PM 2Ring Score of 3

Greatest hits from previous weeks:

Average amount of annual daylight at any place on earth

If this is the wrong group please direct me to the correct one. It seems intuitively obvious that the amount of daylight per annum should be the same for any latitude on earth. For example, 12 hours ...

orbit earth  
user avatar asked by Peter Smith Score of 8
user avatar answered by christopherlovell Score of 11

What is it that distinguishes one atmospheric layer from another?

The atmosphere of a planetary body (assuming it has an atmosphere) is described as being made up of distinct layers. For example, Earth, Saturn and Jupiter all have a stratosphere and a troposphere....

user avatar asked by Montgomery 'monty' Jones Score of 2
user avatar answered by David Hammen Score of 2

Which planets, nebula, and other objects can be seen using Celestron Astromaster 130EQ

I have got a Celestron Astromaster 130EQ telescope, which lens should I use to see the various planets and nebula? When I tried to see Mars it was only a small red dot on scope. As per the ...

telescope terrestrial-planets  
user avatar asked by Anand P S Score of 6
user avatar answered by Florin Andrei Score of 8

How fast is a comet moving when it crosses Earth's orbit?

Is it about the same as Earth's orbital speed?

orbit speed  
user avatar asked by user38715 Score of 5
user avatar answered by Walter Score of 8

What is the distance that the Moon travels during one orbit around the Earth?

Also, does it always take the same amount of time, or does it fractionally differ on each revolution?

the-moon orbit earth distances  
user avatar asked by Asadullah Ali Score of 20
user avatar answered by TildalWave Score of 15

Is the power output at the core of the sun about the same as a compost pile (about 300 watts)?

I read an article at saying that the power output of the sun is about 276.5 watts per cubic metre, similar to that of a compost pile. A compost pile is not incandescent, while the sun is. ...

user avatar asked by Sedumjoy Score of 19
user avatar answered by PM 2Ring Score of 38

Does the moon have days?

As like Earth, does the moon have a day (24 hours). If it has, how many hours are in a moon day?.

time the-moon  
user avatar asked by RANSARA009 Score of 17
user avatar answered by CipherBot Score of 20

Can you answer these questions?

What is the best estimate for the radius of Shoemaker-Levy 9?

I have been digging through various scientific articles on modelling the breakup of SL9 to attempt to ascertain its intial size, yet the various estimates vary tremendously. A radius of 700 m - 1000 m ...

comets tidal-forces  
user avatar asked by Gregor Hartl Watters Score of 2

Do brown dwarf 'stars' fuse simple hydrogen (p-p reaction) at all?

I sometimes read that only deuterium-deuterium fusion can occur in brown dwarfs... And maybe deuterium-proton fusion? To He-3? In order to overcome Coulombic repulsion and, occasionally, fuse, protons ...

star astrophysics stellar-astrophysics brown-dwarf fusion  
user avatar asked by Kurt Hikes Score of 2

How to convert GMST to GMST° (degrees) for calculating RA

For calculating the Right Ascension of the moon I need the GMST (Greenwich Mean Sidereal Time) in Degrees. I have found the formula GMST = 100.4606184 + 0.9856473662862 * D + H * 15, D = number of ...

the-moon right-ascension sidereal-period  
user avatar asked by Ulrich Rosin Score of 2
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