5
votes
2answers
591 views

Where do the heavier elements come from?

Partly inspired by this question, the end result of stellar fusion is Iron-56 (eventually, after some decay). Then it explodes. How/where then to the heavier elements come from. The answer here ...
0
votes
0answers
24 views

What are the up- and downsides of spherical and parabolic mirrors in telescopes?

What are the up- and downsides of spherical and parabolic mirrors in telescopes? I was able to find small bits of information from the web but not a good comparison. Assume the telescope is a ...
0
votes
2answers
131 views

Which eyepieces I can use it for best viewing experience using my exisiting telescope?

Telescope: Orion 09843 SpaceProbe 3,3 inch aperture(76mm), 700mm focal length, eyepieces - 25mm and 10mm focal lengths Hi, I am very happy and excited to see moon craters, jupiter and saturn. And ...
0
votes
2answers
114 views

Precessing of the Earth

It's been known that the Earth's axial tilt varies from 22.5 to 24.5. Does this result in a wobbling while the value of the tilt varies about these two limits? If so, how does it affect the mechanics ...
1
vote
1answer
97 views

Difficulties in finding Jupiter

I am new to astronomy. Jupiter is now visible to the naked eye but I have difficulties in locating it with my (new Newtonian reflector) telescope. The lowest magnification I have is 36X, which I guess ...
2
votes
2answers
190 views

How would Jupiter's brightness relative to our sun seem to a remote observer (observing from a remote star)

Given that Jupiter is 5 AU from our sun and a remote observer viewing our solar system from some other part of our galaxy looks at it. We assume that Jupiter's radius is $11 \times 6700$ km. What ...
0
votes
0answers
67 views

Solar Eclipses for dummies: Step 1 - moon equatorial orbit around a planet without axial tilt

Note 1: I've studied downvoted questions and decided that I either asked too many questions or I sound like I'm setting a fantasy world. So I'm editing my question accordingly. Note 2: I'm a ...
4
votes
1answer
142 views

Estimating the angle covered by the star trails and deducing how long the exposure lasted

How would you estimate the angle covered by the star trails and deduce how long the exposure lasted in the following image? Here is the photo's caption: Star trails beyond the Gemini ...
3
votes
3answers
344 views

What would the night sky look like if Earth orbited an intergalactic star?

If the Earth and its host star were located exactly in-between the Milky Way and Andromeda would the night sky be completely void of light? Would stars be visible to the unaided eye? So there could ...
2
votes
2answers
126 views

Heat from other Stars

Does the Earth receive any heat at all from the millions of other Stars in our Galaxy ? Is it light that is bringing the heat and perhaps it cools down on the long journey in Space getting to the ...
14
votes
2answers
3k views

How did Kepler “guess” his third law from data?

It is amazing that Kepler determined his three laws by looking at data, without a calculator and using only pen and paper. It is conceivable how he proved his laws described the data after he had ...
2
votes
2answers
141 views

What astronomical observations would give conclusive proof of alien life?

There are several ways we are coming closer to answering the question "is there life elsewhere in the universe?". One is by first understanding very well the origin life on our own planet. Another is ...
0
votes
1answer
66 views

What kinds of technologies are required to directly image exoplanets

I have read that immensley powerful telescopes such as the European Extremley Large Telescope will be able to directly image the atmospheres of exoplanets, and even determine their rotation rates. I ...
-4
votes
1answer
59 views

What are the Gamma rays and Cosmic rays effects on humans and equipments? [closed]

First of all not to consider me a conspiracy theorist, but isn't landing on the moon a questionable issue? I am really not an expert in astronomy but let's assume that a moon landing has happened. 1- ...
1
vote
1answer
118 views

What uncertainty does an error bar signify in astronomy?

When an astronomer talks about her/his topic and shows an X/Y-plot with error bars. What should one assume that those error bars represent? 1 standard deviation? Or 2? Or some specific significance ...
3
votes
3answers
452 views

Circular orbits

First of all, I'm studying orbits for a hobby: world building. Unfortunately, my mathematical abilities approach a ridiculous low threshold, which means I am stuck with reading the simplest ...
0
votes
1answer
30 views

L4&L5 positions?

I know that, in L4&L5, the distances to the two main bodies should be equal. Still, how can I calculate that distance with accuracy? How can I know that that distance is inside the equipotential ...
1
vote
4answers
134 views

Relocation to Mars

One billion years into the future and the Sun has swollen in size and it is now not possible to live on Earth due to the heat. Mankind has relocated to Mars where the temperature is more favorable now ...
3
votes
1answer
39 views

Determination of orbital elements for Trans-Neptunian Objects, how?

How are orbits calculated for Trans-Neptunian Objects? I understand there are six standard parameters for defining an orbit (link) but I am not sure how telescope observations translate into these ...
3
votes
0answers
21 views

Estimates for how many Trans-Neptunian Objects there are [duplicate]

The Minor Planet Center shows that we know of about 1350 Trans-Neptunian Objects (TNO's). I think it is safe to assume that we have not found all the TNO's there are to find, even the ones that we ...
0
votes
0answers
57 views

Can an astronaut ever reach a Black Hole theoretically? [duplicate]

Ok, bear with me, while I try to explain the question I have. I read that time slows as we approach a black hole. So, suppose,theoretically, as astronaut is approaching a Black Hole. And he gets ...
1
vote
1answer
62 views

How are parachutes usable in other places than Earth?

Mars landings, Moon landings. . . Wherever I see a documentary or still pictures in Wikipedia, there are parachutes in the landing of rovers. Whenever I see them, I ask myself, "How they can it ...
1
vote
2answers
65 views

Is it proper to refer to objects beyond Neptune as “Kuiper Belt Objects?”

It seems to me that nowadays the more proper term is "Trans-Neptunian Object". Is there any difference between Kuiper Belt Objects and Trans-Neptunian Objects? If not, is one term preferred over the ...
0
votes
0answers
14 views

Binocular with features like gleam night sight advantage?

Im looking for binoculars, I have seen specs like DAY & NIGHT ZOOM BINOCULARS, Full size day and night vision ,binoculars gleam night sight. Are these thing helpful when i look in ...
-2
votes
1answer
59 views

How are molecules detected in space?

Recently the sugar glycoaldehyde was detected in a star system 400 light years from Earth. How exactly are molecules detected in space? I am aware that spectroscopy is used to detect them, but I don't ...
1
vote
1answer
85 views

Hubble HST scheduling algorithm

NASA developed SPIKE: Intelligent Scheduling of Hubble Space Telescope Observations (HST) and this. My question is simple, is there a programming library, preferably in python or C#, to implement the ...
1
vote
5answers
329 views

How far away is the light that would reveal the Big Bang?

I guess theoretically if we could go faster than light, which we clearly cannot, at some point we'd be able to see the big bang itself. Just curious - how far away is that light?
1
vote
1answer
35 views

Why would all places appear to be at the center of the universe's expansion?

I just watched an iMax planetarium video that claimed that no matter where you are in the universe, it will appear that you are at the center of the universe and all things are expanding away from ...
0
votes
1answer
90 views

If Kepler-444 planets existed for 11.2 billion years, why fear for life on Earth after six billion years?

According to recent news, Kepler-444, a 11.2 billion year old star, has a system of five planets. It has a mass of 3/4 of solar mass. So I believe both Kepler 444 and the Sun will share the fate of ...
4
votes
2answers
195 views

How do moons get captured?

[Apologies if this is a duplicate: I feel it ought to be, but my searches have failed]. A moon-sized object is running loose in the Solar System, perhaps after a planetary collision. As it approaches ...
-4
votes
3answers
187 views

Why there are other planets in our solar system? [closed]

Why there are planets in our solar system other than Earth? Only Earth supports life. What is the significance of other planets? Earth receives sunlight from Sun; in a similar way, do we receive any ...
1
vote
1answer
99 views

Does one need to take into account finite gravity speed in N-body simulations?

Most small-scale N-body simulations (e.g., planetary systems, solar system, stellar clusters, ...) use classical Newtonian gravity. Most large-scale N-body simulations (e.g., galaxy clusters, ...) ...
1
vote
2answers
871 views

How much magnification is needed to see planets of solar system?

I have a 3inch Newtonian reflector telescope with 300 mm focal length. I can use highest magnification of 75x using a 4mm eyepiece. But in 75x I can't see details of Jupiter what was expected. Instead ...
5
votes
3answers
332 views

Why are all quasars so far away?

Why are all quasars so far away? If the universe is homogeneous, we could expect to have a homogeneous distribution of quasars, but all of then seem to be far away from Earth. Why is that?
2
votes
1answer
72 views

How long was the hyper inflation phase?

How long was the hyper inflation phase? Haw can we know that it lasted for a period of time and not more or les time?
1
vote
2answers
209 views

Why are gas giants colored the way they are?

As I understand it, Jupiter, Saturn, Uranus, and Neptune are all made primarily from varying proportions of hydrogen and helium. Despite this, Jupiter is very red, Saturn is yellow, and Uranus and ...
0
votes
3answers
204 views

How precisely is planetary tilt defined (the tilt direction, not just the angle)?

The earth's axis is titled 23.4 degrees with respect to the ecliptic. Since this tilt is responsible for the seasons, it's clear that the tilt is in the direction away from the sun on the shortest day ...
2
votes
2answers
380 views

What will happen when landing on Jupiter?

Jupiter is a gas giant, so landing on it will not be like as on Earth, our moon or Mars etc., as it does not have a solid surface like these. If we have a hypothetical spaceship or probe landing on ...
4
votes
1answer
119 views

Entropy of black hole

A line from one of the answers on a different question got me thinking: The simplest way to see this is probably that a black hole has a much higher entropy than a star or even another type of ...
3
votes
2answers
1k views

Does a black hole become a normal star again?

Stars which satisfy the Chandrasekhar limit can become a black hole. What happens to star after it becomes a black hole? Does it regain its status of star?
1
vote
1answer
51 views

Does the cosmic microwave background recede at the speed of light?

Does the cosmic microwave background recede at the speed of light? Is it possible it recedes even faster because of the stretching of space?
2
votes
2answers
84 views

Does the cosmic microwave background change over time?

Does the cosmic microwave background pattern change over time? I would assume it is getting "cooler" as in more redshifted as time passes, but I am more interested if the pattern on the background, ...
1
vote
2answers
113 views

Galaxy rotation curve and dark matter

I am reading "The Essential Cosmic Perspective" by Jeffrey O. Bennett, Megan O. Donahue, Nicholas Schneider, Mark Voit. In Chapter 14, it is stated that an evidence of the presence of dark matter in ...
7
votes
1answer
506 views

How much mass does an object in space need to keep a human on its surface?

Assume there were a roughly spherical object in space like a meteorite or a comet. If I weighed 80kg on Earth, how much mass would be required for an object in space so that I could stay on its ...
0
votes
1answer
70 views

Find the height of the shooting star from the Earth's ground

One night, you and your friend were talking to each other. Your friend far about 20 km. from you. You told your friend that you see the shooting star pass through the sky at altitude of 75 degrees. ...
-1
votes
1answer
81 views

Calculate the time when Arcturus passed through the meridian

If the observer observes Arcturus passed through the meridian about 23:00:00 of 28 April. Find the time that Arcturus passed the meridian in 29 April. And what day does the Arcturus will pass the ...
-2
votes
1answer
162 views

Mass, Radius, Colour, Size, Type of a Star from the Hipparcos Catalog

Using data from the Hipparcos Catalog download file, is there a way to determine the Visual or Apparent Magnitude from the data within? Can I obtain the Mass, Radius, colour, temperature, type ...
0
votes
2answers
83 views

Could there be another planet between Mercury and the Sun?

Could there be another planet between Mercury and the Sun? Kepler found a lot of planets orbiting its star even 20 times closer than Mercury. If there were such planets in our system - would it be ...
2
votes
2answers
148 views

In geocentric models, did the earth rotate?

Under geocentric models, did the earth rotate around its axis? I assume that if the earth rotated around its axis, then the sun would not have to orbit around the earth at a very fast rate, whereas ...
5
votes
3answers
132 views

Is it possible to disprove geocentrism without telescopes?

The development of telescopes enabled the discovery of moons orbiting around Jupiter, and the existence of a full set of phases of Venus, as opposed to a limited set which would be predicted by ...

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