Questions tagged [astronomy]

Questions more about celestial bodies themselves than exploration of them.

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If there's nothing special about Pluto, why was it discovered so early?

Pluto was recently re-classified, losing its official status as the ninth planet, because a bunch of other dwarf planets were found in its orbital region that were too numerous and insignificant to ...
Mason Wheeler's user avatar
37 votes
4 answers
7k views

Why is JWST parked in sunlight, rather than using a nuclear battery?

The James Webb Space Telescope (JWST) is in a halo orbit around L2, at a sufficient radius around the Lagrange point that it is in perpetual sunlight. That allows it to have predictable solar power, ...
pde's user avatar
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24 votes
2 answers
2k views

Is there a Martian "North Star", usable as Earth's North Star?

Mars has a different axial tilt than Earth. It stands to reason that the constellations will remain identical from Mars, but their locations will be somewhat different. On Earth, the North Star is ...
PearsonArtPhoto's user avatar
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20 votes
2 answers
4k views

Are images of exoplanets' surfaces technically possible?

While already even taking an image of an extra solar planet sounds like science fiction to me, is it technically possible by what we know now to take also more detailed images of extraterrestrial ...
J. Doe's user avatar
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18 votes
5 answers
4k views

Would a lunar telescope provide a significant improvement over terrestrial based equipment?

As I understand it, the moon makes for an ideal location for a telescope because it offers environmental factors that are unlike anything achievable on earth: A lack of atmosphere, light pollution, ...
Eliot G York's user avatar
15 votes
2 answers
2k views

Why would Kepler rotate towards Earth to transfer data?

A question from here: "Why would Kepler rotate towards Earth instead of having an antenna always directed to Earth"?
J. Doe's user avatar
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14 votes
2 answers
2k views

Could we detect a nuclear explosion near Proxima Centauri?

How big would a nuclear explosion in open space around 1 AU from Proxima Centauri have to be for it to be detectable with current technology? Assume best-case scenarios, such as we're specifically ...
Joe L.'s user avatar
  • 402
12 votes
2 answers
604 views

Interstellar eavesdropping

For about a century, humanity has broadcasted noise to space in the form of TV broadcasts, radio, etc... The nearest star is 4.242 light-years away, so for about 90 years, aliens -- if they exist in ...
strand's user avatar
  • 121
11 votes
2 answers
2k views

Would we be able to tell if another civilisation built a Dyson sphere (or similar) around a distant star if we were looking for it?

A list of my thoughts/assumptions we have a good understanding of how stars live and die, so a "healthy" star (I assume you would only build a Dyson sphere around a star that's going to ...
Sam Dean's user avatar
  • 213
11 votes
1 answer
507 views

Is it possible for moons to have their own moons?

I'm wondering, if it's possible for moons to have their own natural satellites, something big enough to be spherical? Stars have planets, planets have moons. Is it possible that moons have moons too?
shunryu111's user avatar
10 votes
2 answers
619 views

Was Hipparcos Satellite really necessary? Can't Hubble do everything that Hipparcos did?

I've been reading about the Hipparcos Satellite recently and it seems it was the first big telescope with precision-measuring devices to accurately pinpoint a star's location in the sky. I know ...
DrZ214's user avatar
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9 votes
1 answer
483 views

Why were Nix, Cerberos and Styx discovered later than Charon?

Charon, a moon of Pluto, was discovered in 1978. Today we know that Pluto has three additional moons, but they were discovered 3 decades later? Also, Hubble Space Telescope was in operation since 1990 ...
Zoltán Schmidt's user avatar
9 votes
3 answers
379 views

What is the current state of affairs concerning space telescopes?

With the Hubble telescope to be decommissioned any time now, and the James Webb Space Telescope at least in 2018 and unlikely to be active while Hubble still remains, will there be a gap when we have ...
SF.'s user avatar
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8 votes
2 answers
995 views

How to find orbital elements of a binary system

I'm trying to find the rate of precession of a binary system consists of two similar mass stars A and B, so I need to find the value of the argument of periapsis $\omega$ first, with velocity and ...
Sam's user avatar
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8 votes
1 answer
4k views

Is there a telescope on board the ISS?

I am wondering if there is a telescope in or outside the ISS that has been used for astronomical imaging? I have seen here that there is already a Celestron telescope on board but it is only used for ...
Dean's user avatar
  • 429
8 votes
2 answers
491 views

NASA just announced 715 new exoplanets were discovered, what do we know about them?

I have been trying to find information on how far away these new exoplanets are from Sol. Does anybody have a map or a table that shows their distance to us in light years. There only seem to be 100 ...
Maelish's user avatar
  • 879
7 votes
2 answers
256 views

Detection of 2015 TB145 (Halloween asteroid)

Why was 2015 TB145 detected just weeks before its closest approach, while so many other asteroids (which will make closer approach or farther approach) are detected years before? What made this ...
r2_d2's user avatar
  • 779
7 votes
1 answer
258 views

What are the effects of orbital reflectors and advertising on scientific observation?

There's a couple of startups and initiatives which are proposing "space billboards" which have been getting a lot of bad press recently. Most of the proposals involve a bunch of cubesats with large ...
Dragongeek's user avatar
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6 votes
4 answers
2k views

What's the orange star I can see in the sky right now? [closed]

Directly above the left shoulder of Orion, as I hold my closed fist maybe eight or ten inches in front of my face the distance between them is approximately from my knuckle to my wrist. A very bright ...
Pelinore's user avatar
  • 712
6 votes
1 answer
2k views

Are there any natural circular orbits?

I just saw How does orbital eccentricity affect positions of Lagrange points $L_4$ and $L_5$? and it questions the difference between circular and elliptical orbits. We know the Moon does not have a ...
James Jenkins's user avatar
6 votes
4 answers
420 views

Are there any other Earth-like planets in the universe?

There are many galaxies in the universe. Is there any other Earth-like planet out there?
Krishna Raja's user avatar
6 votes
0 answers
168 views

What are the contributions of ancient Indian astronomers in mapping of the solar system and galaxies?

In the history of astronomy we usually come up with the name of European astronomers like Kepler and Galileo. Earlier Indian astronomers, for example Aryabhata and Bhaskaracharya, are not usually ...
Bhaskar Bhadra's user avatar
6 votes
2 answers
1k views

What will happen to JWST after its 10 year mission?

JWST launched recently. https://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Orbit JWST needs to use propellant to maintain its halo orbit around L2, which provides an upper limit to its designed ...
spraff's user avatar
  • 171
5 votes
3 answers
948 views

Does the Earth have any Trojan asteroids?

Are there any known Trojan objects residing in the Sun-Earth L4 (SEL4) and L5 (SEL5) Lagrange points, also named "Greek" and "Trojan" groups, respectively?
Thunder's user avatar
  • 119
5 votes
3 answers
466 views

Speed at aphelion is decreasing for Parker Solar Probe with each new orbit despite being closer to the Sun

Sorry for the really bad picture I am looking at some data from the Parker Solar Probe mission and I was looking at the speeds of PSP at perihelion and aphelion at each new, different, orbit (the ...
Alexander Ivanov's user avatar
5 votes
1 answer
159 views

What is the Dark Matter Particle Explorer telescope?

China's new mission DAMPE will launch a dark matter particle telescope to detect and study the evidence of dark matter. How does this telescope work? What is expected from the mission?
r2_d2's user avatar
  • 779
4 votes
3 answers
268 views

Why do we search for extra-terrestrial water?

When searching for signs of extra-terrestrial life, the key primary challenge as of now seems to be searching for signs of water on other planets. Presumably, this is because on Earth, water is ...
Karnivaurus's user avatar
4 votes
3 answers
536 views

A black cube 1 mile per side appears in geosynchronous orbit around the earth. Who would spot it and how would they do it? How easy would it be?

This is not intended to be a math question, so much as an understanding of how the current technology and techniques would view this problem.
john's user avatar
  • 41
4 votes
3 answers
312 views

What would be merits of placing space telescope after the asteroid belt or closer to the Kupier belt?

I want to know what difference does it make, in terms of observations made and the benefits for the astronomical society if we place a space telescope after the asteroid belt or near the Kuiper belt. ...
Bharath Simha Reddy's user avatar
4 votes
1 answer
416 views

Can Chang'e 3 take photos of the stars from the moon

Chang'e 3 now on the Lunar surface has imaged the Earth. Is it possible for that same camera to take a time exposure and show us the stars?
Gary Whatzisname's user avatar
4 votes
0 answers
39 views

What observatories provide data similar to USNO? [closed]

USNO(the United States Naval Observatory) generates positions for the celestial bodies(planets, moons,stars) and provide in a form of .bsp files and their ...
sigrlami's user avatar
  • 203
3 votes
1 answer
194 views

Is there any Scientific Benefit to the Lower Albedo levels on the Darkside of the Moon?

I was reading the answers to this question: What did the sky actually look like from the Moon? And it got me thinking... What, if any, astronomy tasks could be performed better on the lunar far side ...
Magic Octopus Urn's user avatar
3 votes
2 answers
312 views

Recent anomaly in star system detected by Kepler mission

Recently the Kepler Mission detected a anomaly in a star system (KIC 8462852) that people are speculating could be a sign of intelligent life (aliens) being cause for anomaly. What was exactly going ...
r2_d2's user avatar
  • 779
3 votes
1 answer
255 views

Did Skylab astronauts really "go outside" to look at comet Kohoutek? If so, why?

Today in The BBC's Skylab: The myth of the mutiny in space it says: The Skylab space station was a research platform in orbit where astronauts helped scientists to study the human body's response to ...
uhoh's user avatar
  • 149k
3 votes
1 answer
68 views

At what wavelengths and for what particle types have astronomical objects been imaged or at least directionally resolved from the ISS?

The ISS has an X-ray telescope called NICER and this answer in Astronomy SE (and links therein) explain that it was able to show that there are hot spots clustered near one pole of the pulsar PSR ...
uhoh's user avatar
  • 149k
3 votes
2 answers
184 views

How to explain the fast motion of the Starlink satellite in this video?

My friend in Łódź sent me this video today: https://i.imgur.com/EmpNzfs.mp4 This was observed in Widzew district, at 20:42 Warsaw time. He has two questions: given that it looks like it's Starlink ...
d33tah's user avatar
  • 131
3 votes
1 answer
219 views

What is the relationship between the periapsis altitude and the change in velocity in a gravity assist?

In a gravity assist maneuver if I were to decrease the distance from the rocket to the periapsis of the planet it is orbiting (I believe this is called the periapsis altitude but I may be wrong) it ...
Alexander Ivanov's user avatar
2 votes
1 answer
128 views

Kinematics help

If a constant acceleration starship started at rest, then accelerated at 25G (245m/s^2) how long would it take to fly an AU (149 597 871 kilometers)? I am a writer, so I have no experience with ...
Will's user avatar
  • 21
2 votes
2 answers
870 views

Why does the Moon only show its near side while orbiting the Earth? [closed]

When we look at the Moon in the night sky, why do we always see the same side every night?
Austin Phillips's user avatar
2 votes
1 answer
294 views

When will the telescope that last saw Starman/Roadster be able to see it again?

According to this answer to When was the last time that Starman/Roadster was seen? it was last seen by Earthlings at least at 2018-03-19 03:22:33 UTC by a 1 meter ...
uhoh's user avatar
  • 149k
2 votes
1 answer
228 views

How to become an astronaut?

I am a pure/applied mathematics student at Tehran University. About 2 or 3 years later I will get my bachelor's degree and start studying master's in applied math or theoretical physics. And maybe I ...
Parsa Khavarinejad's user avatar
2 votes
1 answer
2k views

Determine the eccentricity of the orbit

A satellite is in orbit at an altitude of 62.5km, with a speed along the earth-relative position vector of 3.98km/s, and a speed perpendicular to the earth-relative position vector of 7.763km/s. What ...
Carl Jonson's user avatar
2 votes
1 answer
175 views

Where do the poles of the Solar System point? [closed]

The solar system is like a big rotating disk, so it has an axis. Where do the two ends of the axis point in space? To put it another way, where in the sky are the two furthest points from the ...
gostone's user avatar
  • 29
2 votes
1 answer
134 views

How do you calculate the length of a planets shadow?

Given the diameter of the sun, the diameter of a planet, and the distance between them, how do you calculate the length of the planets shadow?
Innovine's user avatar
  • 4,625
2 votes
1 answer
225 views

Lunar surface illumination levels

I am trying to determine the lunar surface near or far side daytime illumination levels in Lux or foot-candles but there seems to be no directly measured values available. I did find this information ...
Solon's user avatar
  • 35
2 votes
1 answer
206 views

Effect of incoming velocity on change in velocity in a gravity assist

In a gravity assist does the incoming velocity of a space craft effect how much speed it gains. For example say a rocket was approaching Jupiter for a gravity assist with speed v and another rocket ...
Alexander Ivanov's user avatar
2 votes
1 answer
125 views

Moon's orbit and its phases

After learning what apogee and perigee are, I'm curious to know if/when these stages align with particular phases of the Moon? I'm obviously assuming that the orbit has a repeating pattern, but maybe ...
Ricky's user avatar
  • 443
2 votes
0 answers
21 views

Did Starlink's experimental Darksat help reduce brightness? [duplicate]

Did Darksat's visor like coverings to its parabolic antennas reduce the brightness or was it a failure. Or is SpaceX devoleping any other mechanisms or manuveres to counter this problem?
CrusaderCaped432's user avatar
1 vote
2 answers
303 views

Is there any plan to send a space telescope to orbit around gas giants?

While sending a space probe to orbit around a gas giant is often heard of, are there plans to send a space telescope to orbit around gas giants, so that it can operate far away from the sun, or even ...
Gstestso's user avatar
  • 817
1 vote
1 answer
3k views

Does the Sun actually move on its own, or does it move with the Solar system? [closed]

I'm curious, does the Sun actually move? The concept behind the question is, if you wear a shirt and you move, does the shirt actually move? Like the Solar system orbits around the Milky Way, but does ...
Tinus Jackson's user avatar