The science dealing with objects and phenomena located beyond Earth. In particular, this applies to observations and data. At its core, astronomy is the physically informed cataloging and classifying of the contents of the universe in order to better understand what is out there.
9
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131 views
Where does the dust on the moon come from?
From the Apollo missions we know that the moon is covered with dust. Where does it come from? Is it from the erosion of the moon rock? By what? Or by accretion of dust from space? Which comes from ...
2
votes
1answer
10 views
Are there trends in the number of meteors in a shower year on year?
Some years the Leonids are amazing, other years there are very few - are these predictable at all, following trends or at least reasonably accurate predictions?
2
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3answers
31 views
Where can I find a list of when I can see something in the sky?
My son is very keen on Astronomy but I don't know when there are meteor showers or something else that would be worth going out to the country to see. Last year we went to see a meteor shower, but I ...
4
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2answers
14 views
How bright will an asteroid be?
In the news, it has been stated that there will be a fairly large asteroid passing fairly close to Earth soon. I've been trying to find a good observation guide, including determining how bright it ...
7
votes
1answer
54 views
What's the most accepted theory for Blue Stragglers These Days?
I'm working on a post against a recent creationism article about blue stragglers. From when I was in undergrad, the general explanation was that they were likely second generation stars within ...
3
votes
2answers
111 views
What is a good introductory text to astronomy
What is a good and easy to read introductory text for an adult with limited basic scientific knowledge to astronomy for someone without a telescope and lives in a big city and why do you think that ...
5
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2answers
37 views
Does Mercury have a balmy spot?
From Wikipedia:
Although the daylight temperature at the surface of Mercury is generally extremely high, observations strongly suggest that ice exists on Mercury.
Does that mean there could be a ...
8
votes
3answers
260 views
Why is this radio telescope's reflector spherical and not parabolic?
This is the Arecibo Observatory in Arecibo, Puerto Rico. Its reflector is spherical, measuring 1,001 ft. in diameter. It is considered the most sensitive radio telescope on Earth, but the fact that ...
2
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0answers
135 views
Angular Diameter, Parallax - Perceived size of Objects
I'm currently in the process of writing a 2.5D Application that should display the perceived size of an Object. For example, When I have a ball that has a diameter of 1meter, how big would it appear ...
2
votes
1answer
58 views
Get time from sun Azimuth
I want to know if I can determine the time where the sun's azimuth is at a given value.
In other words, I want a function that takes the sun azimuth along with longitude or time zone and outputs the ...
13
votes
1answer
644 views
Which way do spiral galaxies rotate?
Is it known whether spiral galaxies typically (or exclusively?) rotate with the arms trailing or facing?
Intuitively it feels weird to think of the arms as facing the direction of rotation, but ...
4
votes
1answer
41 views
How fast is the Cosmic Microwave Background Radiation (CMBR) changing?
I know that the Cosmic Microwave Background Radiation (CMBR) is the leftover radiation from the "surface of last scattering".
However, at every instant the surface is changing (at the rate of flow ...
3
votes
0answers
74 views
Parallax Cloud Displacement - Angular Distance from Geostationary Satellite
When observing clouds from a geostationary satellite, they appear displaced because of the parallax effect. The satellite looks at the clouds "at an angle" and it projects them on a point of the earth ...
4
votes
1answer
83 views
How is the atmosphere composition of astronomical objects in solar system determined?
How is the atmosphere composition of astronomical objects, for example triton, the moon of neptune, determined?
2
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2answers
772 views
How much of sky can be seen on a typical night from a mid-latitude location?
I'm at about 40deg north so, assuming a clear southern horizon, I can't see things below about -30 or so (I actually don't know how far south). I also have a large portion that is circumpolar so it's ...
3
votes
1answer
60 views
What could this very dark planet be made of?
I was reading about the planet TrES-2b which is less reflective than charcoal. What could possibly be its composition?
4
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3answers
179 views
Pleiades through a 15x 76 mm telescope
How clearly can the stars of the Pleiades cluster be seen through a 15x telescope (for example, FunScope)?
6
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1answer
482 views
What are the minimum telescope requirements to view a nice spiral galaxy?
I would like to view some spiral galaxy. However, I would prefer not to spend lots of $$$. What are the minimum specs a telescope must have to resolve detail in a spiral galaxy?
2
votes
3answers
65 views
Name for celestial “Prime Meridian”?
Is there name for the line that goes from celestial pole to pole at RA 0 degrees 0 minutes 0 seconds? On Earth we would call it the Prime Meridian. Is it called the "Celestial Meridian"?
0
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0answers
39 views
Anyone Know Details About the New Nobel Prizes in Physics and Chemistry? [closed]
The physics prize seems to be in astronomy but, I guess, that falls into the realm of physics for the lack of a separate astronomy prize. The chemistry prize, however, seems to also belong to physics ...
4
votes
1answer
644 views
Density of stars near the center of the Milky Way
At night, I can look up and see the Milky Way across the sky. My question is, supposing our solar system was, instead of way out on an 'arm' of the galaxy, if we were near the galactic center. Would ...
13
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5answers
789 views
Telescope for 6 year old and dad new to astronomy
What's a good telescope for my 6 year old? We're both brand new to telescopes in general, but love space, stars, planets, cosmology, etc. Happy to spend up to $200 to start. Maybe more for a good ...
4
votes
1answer
268 views
Is there a simple yet accurate formula for where on Earth the Sun and Moon are directly overhead?
I'm trying to improve a site that shows the region of the Earth currently under daylight, and I
need a formula that, given the current time, tells where
(latitude/longitude) the sun and moon are ...
5
votes
2answers
52 views
Tropical year is 27s/year off from Gregorian year?
http://hpiers.obspm.fr/eop-pc/models/constants.html states the
tropical year is $365.242190402$ days.
The Gregorian calendar's average year is $365.2425$ days (every 4th year
a leap year, except ...
4
votes
1answer
19 views
What demonstrations for a five-hour optical and radio astronomy workshop? [closed]
I volunteer at a group that has restored the oldest German radio telescope. We are now at a point where we want to invite interested amateur astronomers and school children to workshops. I'm currently ...
12
votes
1answer
90 views
Why don't stars in globular clusters all orbit in the same plane?
Globular clusters like Omega Centauri certainly don't seem to be very coplanar at all.
In other words, why doesn't the explanation at Why are our planets in the solar system all on the same ...
0
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1answer
27 views
Where to get hard historical and trend data related to reentry of satellites like UARS [closed]
NASA is providing very brief updates on the reentry of the UARS satellite. They also published an extensive study of the Re-entry and risk assessment for the NASA Upper Atmosphere Research Satellite ...
4
votes
3answers
171 views
What is the minimum magnification needed for an instrument to see all the Messier objects?
I know someone that wants to buy a 60cm (1.5 inch) refractor and I thought about recommending what to look at the Messier objects. And I was wondering, can he see all these objects with that refractor ...
0
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3answers
77 views
Why is it hard to write a computer program to detect patterns which planethunters is asking us to figure out? [closed]
I recently came across this site http://www.planethunters.org. It shows brightness observed for a star vs time. It asks questions like if star is exhibiting variable or fixed pattern. Later it asks if ...
6
votes
3answers
170 views
“Reverse engineering” of a horoscope?
I'll start with a disclaimer -- this is not a question about astrology itself, I'm neither trying to refute nor to defend astrology. I'm interested in purely technical things, which are mostly ...
4
votes
3answers
120 views
Fall/Winter Viewing
I live in Seattle and am thinking of purchasing a telescope. Is fall/winter a decent time of year for viewing (aside from summer)? Are there any major viewings/events during that this of year?
I know ...
-1
votes
2answers
2k views
Celestron NexStar 6 SE vs. Orion XT8 [closed]
I'm interested in purchasing a new telescope and have narrowed it down to the NexStar 6 SE vs. the Orion XT8.
I'd like to be able to get into astrophotography and read that having the Go-To ...
2
votes
2answers
47 views
Photographs of galaxies many light years far from the Earth
Using ground-based telescopes or the Hubble Space Telescope, astronomers take photographs of galaxies which are many light years from the Earth. Does it mean those photographs are as old as the ...
8
votes
3answers
180 views
Are planetary orbits measured from the Sun's surface or centre?
I would imagine planetary orbits are measured from the Sun's centre and not its surface. Is that true?
I can't find anywhere that actually states this.
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3answers
29 views
Why can't Jupiter be seen over Thanksgiving break?
As of these past few days, Jupiter can be seen in the sky, correct? Around Thanksgiving, why can't it be seen?
2
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2answers
19 views
What physical interactions actually make single stars leave their binary companions at formation?
From an interesting ScienceDaily article, I read this
Before the groups of stars disperse, binary stars move through their
birth sites and the group studied how they interact with other stars
...
0
votes
1answer
134 views
Is water necessary for forming the sedimentary rocks found on Mars' surface?
So, I've just been reading a recent ScienceDaily article, and came across this interesting quote
"Clays form in more neutral, less acidic conditions than the
sulfate-rich sandstones we've been ...
9
votes
1answer
187 views
How vacuous is intergalactic space?
You often hear intergalactic space is an example for a very good vacuum. But how vacuos is space between galaxy clusters and inside a huge void structure? Are there papers quoting a ...
14
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2answers
166 views
What percent of planets are in the position that they could be viewed edge-on from Earth? (and thus able to undergo transits)
Star number 12644769 from the Kepler Input Catalog was identified as
an eclipsing binary with a 41-day period, from the detection of its
mutual eclipses (9). Eclipses occur because the orbital ...
6
votes
1answer
76 views
Axial Tilt and precession rate of exoplanets
The Earth's axis is 23.5 degrees away from othogonality to the ecliptic, and it takes about 26 000 years for it to precess fully. I have neither an intuitive sense nor the formula for precession ...
3
votes
1answer
52 views
Phases of the moon video
I am an educator, and I am looking for a specific video. In the video, they ask some middle school students and some college graduates about why the moon has phases. Most of the students in both the ...
3
votes
2answers
44 views
Computing period, semi-major axis of binary
I have mass, $g$, and luminosity of each of the stars in a binary system, extracted from a model. I calculated the individual radii from $g$ and the mass. I am trying to compute $a$, but I seem to be ...
6
votes
3answers
39 views
How to get started in Astronomy (UK based) [closed]
I have always been interested in space and astronomy (in my youth - I wanted to be an astronaut).
However for various reasons, I never quite got started. I now want to get started - small but ...
16
votes
5answers
5k views
How long does it take to travel 36 light years with tolerable acceleration and deceleration?
The recent discovery of HD85512b only 36 light years from Earth has promising attributes to harbor life. Assuming we want to travel there, we cannot instantaneously jump to light speed, (StarTrek ...
4
votes
4answers
268 views
Creating a Star Map
I have a set of data on all the stars (well, to a magnitude of 9 or so) with the values of the following properties:
magnitude,
right ascension and,
declination.
Now I'd like to create a planar ...
3
votes
3answers
92 views
On what planar regions are the Earth, Moon.. for that matter, all astronomical bodies, placed in the Universe?
When we are on Earth, we look UP in the Sky to see the Moon. How do we have to look at Earth from Moon.. Is it the way ? If so, how are these bodies actually placed in the space?
Are all astronomical ...
9
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1answer
277 views
If the Earth didn't rotate, how would a Foucault pendulum work?
How does the Foucault pendulum work exactly, and would it work at all, if the Earth didn't rotate?
10
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4answers
10k views
Can the “Milky Way” galaxy be seen by the naked eye in a clear sky?
Is this photo "real"? Are the stars not super-imposed in the image?
2
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2answers
517 views
Formula for Rotation curves of Galaxies
To ask a more specific one for the rotation curves of elliptical galaxies, and hope from there to later understand the dynamics of spiral galaxies.
Treating the galaxy as an isothermal ...
3
votes
2answers
38 views
Particular targets of high angular resolution infrared telescopes
I work in the field of infrared interferometry, specifically instrumentation.
As such, I need to be aware of the science goals of such an instrument. Is there a quick list of important and ...
