1
vote
0answers
15 views

Milky Way stellar number density : is the stated equation in this paper incorrect?

The paper is : http://www.astro.washington.edu/users/ivezic/Publications/tomographyI.pdf The equation is equation #23 in the paper. It's a model for the density of stars in the Milky Way's disk. It ...
5
votes
1answer
47 views

How can we tell the difference between matter and antimatter by observation in space?

I just was wondering and searching on the internet with little luck in the topic. On Antimatter Wiki they tell the observable universe is built up by matter. I read antimatter can be detected in ...
0
votes
0answers
5 views

Finding the northernmost latitude in a great circle that passes through two points on the sphere [migrated]

I'm trying to prove that: a) If A and B are two places in the earth's surface with the same latitude Φ, and the difference between their longitudes is 2l then the highest latitude reached by the ...
1
vote
0answers
35 views

Longest and shortest wavelength

What is the longest and what is the shortest wavelength of light? How fast would a light-emitting object have to recede in order to shift the frequency of light to increase the wavelength from the ...
0
votes
1answer
24 views

Attraction to barycenter

If an object was a distance from a planet away that equaled the distance from the object to a moon of the said planet, would it be drawn into the direction of the barycenter as it is the common center ...
1
vote
2answers
22 views

Globular cluster star density as a function of distance from the center

Context: I want to simulate globular clusters in a simple way, just to display the positions of stars. Assuming isotropy, what would be a reasonable model of the stellar number density as a function ...
0
votes
1answer
57 views

How would the solar system look in a Geocentric model?

If I fix the Earth as the center of the solar system, what would this look like? Are there any good images? How complex is this system?
2
votes
1answer
49 views

Is radiation from neutron stars delayed by time dilation?

I understand a neutron star to be the densest stuff that can exist without becoming a black hole, the densest thing which directly gives off radiation we can detect. At the event horizon of a black ...
0
votes
2answers
39 views

The Fermi paradox

Ok so I was reading about the Fermi paradox, assuming life will form and thrive where possible as soon as possible and there is a very probable chance many other earths formed would they have started ...
0
votes
1answer
22 views

Exoplanets and relativity [duplicate]

Ok, so I have read about how exoplanets are found using all sorts of genius methods. I also understand the further an obect in a telescope is the further into the past I am looking. So given that ...
0
votes
1answer
65 views

What supernova has created the iron currently found in Earth core?

Iron is generated by stars in a certain part of their life cycle. Earth contains a lot of iron inside, however it is clear that this iron could have not been generated in a star in close proximity. If ...
2
votes
3answers
194 views

What happens to galaxies when they die?

Stars explode when they die and blast heavy elements into space. Do galaxies do the same thing?
0
votes
1answer
25 views

Standardized “constellation” regions?

The current system of constellations is historical and has kind of arbitrary boundaries. This has a number of obvious downsides: Difficult to define boundaries need complex tables to express Each ...
-1
votes
0answers
26 views

atoms and creation [on hold]

I apologize if this makes me seem like an idiot but I have to ask. During conception, a sperm meets an egg. These two start dividing up and multiplying and eventually form an infant human. Where did ...
1
vote
1answer
23 views

What is a typical value for core-to-star efficiency?

I was reading Unfolding the Laws of Star Formation: The Density Distribution of Molecular Clouds by Kainulainen et al., which discusses star formation rates and efficiencies. One variable used is ...
0
votes
1answer
18 views

Occurence of Venusian transits

As transits of Venus come in pairs each seperated by 8 years, wouldn't that imply an accurate ratio between earths and Venus' revolution period? I've found the ratio to be about 0.681. I presume one ...
3
votes
1answer
61 views

Where might a semi proficient amateur analyst participate in meaningful astronomical efforts

I am a retired engineer that has an ongoing interest in space efforts. In my youth I did work on the Apollo program but on propulsion and vehicle thermal control: not flight dynamics. I have ...
-1
votes
1answer
58 views

Evidence that galaxies are made of billions of stars?

What is the evidence that galaxies are made of billions of stars? Even faint galaxies? Can spectral analysis distinguish galaxies from individual stars?
0
votes
0answers
9 views

If conjuncting planets are 1/3° apart (geocentric) at 15° elongation how low could the elongation at closest approach be?

Does anyone even have a rough idea? I don't know which pairs of planets can appear close for longer without changing elongation too slow like Mars does when behind the Sun.
0
votes
3answers
90 views

“Up” and “down” in Space

From my understanding, "up" and "down" in space is going towards (down) an object's gravitational pull or (up) which is going away from it. I get confused with this explanation, and I believe simply ...
0
votes
1answer
71 views

Finding Latitude and Longitude of a person or of where a picture was taken

this is my first post on the Astronomy stack exchange site. Please let me know how this question is based on y'all's generally accepted criteria for a good question as well as possible improvements. ...
0
votes
1answer
85 views

Has the sun become way brighter the last years?

Up to last year, I never got blinded by the sun in everyday situations (e.g. running towards it), at no time of the year I was. But since last christmas, it occured to me more often that I cannot ...
1
vote
1answer
27 views

Difference in redshift between 2 interacting galaxies

I have a galaxy 'A', say at redshift 1. Let's suppose this galaxy has no peculiar velocity. What would be the redshift of another galaxy 'B', that has a radial velocity of 500 km/s, relative to A? ...
2
votes
4answers
511 views

Which is more rare: Lunar eclipse or Solar eclipse?

Which is more rare: Lunar eclipse or Solar eclipse? Please explain why either one is more rare than the other. Thank you in advance for your inputs.
2
votes
1answer
87 views

Stars in the sky

Are the stars we can see with the naked eye in the night sky only from our Milky Way galaxy or can we see stars from Andromeda? I am aware we can see other celestial objects like nebulas and the ...
4
votes
1answer
170 views

Why can we see stars but not astronaut on the moon

A question came up today in astronomy class and it got me wondering all night. How is it that if stars are so far away, we can see them so clearly but we cannot see astronauts on the moon.
1
vote
2answers
57 views

Calculating the age of the universe

Is the calculated age of the universe that of the visible universe or the entire universe? I dont know how the age is calculated but if it is believed that all we see visibly IS the entire universe ...
1
vote
3answers
145 views

Mini black holes, a possible result of the LHC experiment at CERN

A scientist at CERN LHC (Large Hadron Collider) was asked during an interview about the possible results and consequences of operating the LHC at full power of collision in the near future, one of the ...
-1
votes
1answer
25 views

Two body transient solution

In the two body problem, if each body is given an initial condition as a momentum vector, what is the transient part of the solution as it settles into the steady state orbit?
-1
votes
0answers
26 views

What are the implications from the fact that Relativity and QM did not predict intergalactic space, big bang, inflation or dark matter? [closed]

Cosmology has two very successful theories, Quantum Mechanics and Einstein's theory of Relativity. But they are unrelated to each other. And their predictive powers have been limited, being equally ...
2
votes
2answers
94 views

Claim that 30-m class telescopes will have resolution far superior to Hubble: true?

This article makes the claim that the Giant Magellan Telescope (GMT, number 4 in the list) will have resolution 10 times better than that of Hubble, while the Thirty Meter Telescope (TMT, number 3 in ...
0
votes
1answer
13 views

Is it possible to get the distance to a star in the IPHAS DR2 catalog?

I'm looking at the IPHAS DR2 catalog. It has the Right Ascension and Declination but I'm not seeing any distance information (lightyears or parsecs). I'm wondering, given the columns in the dataset, ...
0
votes
0answers
46 views

What would this moving point of light be?

Tonight (10:00 PM EST Middlesex County, Mass.) when looking at the mostly clear sky I observed what I at first believed was a meteor. This point of light was moving east to northeast and that would be ...
0
votes
0answers
33 views

How to implement DCDFT to get S vs T graph

I was trying to implement DCDFT (Date Compensated DFT) (Ferraz Mello's) to a tabular data which I had saved in an Excel file. After searching the internet thoroughly, I came across Vstar software, ...
6
votes
0answers
32 views

Why doesn't the New Horizons probe fly any nearer than 10,000 km from Pluto? [migrated]

New Horizons is intended to pass within 10,000 km of Pluto on its flyby on July 14. This will give a maximum resolution on the surface of 50m per pixel. This seems to me a bit of a waste, when it ...
1
vote
0answers
34 views

Use Pluto's gravitation to reach the next dwarf planet [migrated]

Why doesn't New Horizons fly by nearer to Pluto so the gravitational pull would slingshot the probe to one of the next dwarf planets in the outer solar system (Eris, Haumea, Makemake,...)? I would ...
0
votes
0answers
20 views

Tonight sky - deep sky objects

programmatically how can i get the list of Deep sky objects that will transit the meridian in my Latitude and longitude? Any online API?
1
vote
0answers
46 views

Telescope Problems

I currently own a telescope, I'm an amateur astronomer and currently just trying to view the moon. I own the Celestron PowerSeeker 70AZ. Link for information on the telescope: ...
0
votes
1answer
47 views

Cosmological deflation?

Wikipedia tells us: In physical cosmology, cosmic inflation, cosmological inflation, or just inflation is the exponential expansion of space in the early universe. The inflationary epoch lasted ...
1
vote
2answers
106 views

On a log-log plot of surface gravity to planet mass, what is the meaning of the y-intercept?

I am playing around with data from exoplanets.org, and am interested in the plot of surface gravity to planet mass. I reproduced this plot after downloading their data and performed a non-linear ...
6
votes
2answers
138 views

Why does the Solar System have no (natural) satellites of satellites?

What are the conditions for a planetary moon to have a satellite of its own? How far do the Solar System's bodies fall from the necessary threshold?
0
votes
1answer
41 views

What is the most populated/numerous stellar system in which the orbits of all objects are known?

I posed a question or two on here a couple months or so ago about the orbital patterns of each of the seven stars in the two septenary star systems Nu Scorpii and AR Cassiopeiae. They remain ...
0
votes
0answers
5 views

Smallest lunar probe that can be made using today's technology [migrated]

Suppose we want to do a lunar sample return mission. We can then launch a small rocket from the ISS that carries a small probe to the Moon. It will collect a sample and then return to the ISS. ...
1
vote
4answers
130 views

Is there a way to tell what the surface of a planet is like?

Kepler-442b I'm doing a project in which I need to find a planet within our galaxy that might be habitable. I found this planet that is within its stellar system's habitable zone, and due to research ...
0
votes
2answers
45 views

Would dark energy save the earth for a while as the sun heats up?

Would the expansion of space (e.g. dark energy) move the earth further away from the sun over time, possibly saving us for perhaps a few billion years as the sun heats up? Scientists now tend to ...
1
vote
1answer
77 views

Star versus Black Hole

I'm making a simplified animation for college project on how a star reacts with a black hole. I had known that a black hole sucks in everything and thus should be doing the same for stars. But upon my ...
-4
votes
1answer
46 views

Could our Sun be a companion star of a massive black hole?

Can we track its orbit well now? There is any study that may indicate our sun may be a companion of a big black hole? What is the current constrain about its orbit now? There is a 1000 solar mass ...
1
vote
1answer
75 views

How can a supernova affect black hole in a binary system?

Suppose in a binary stars system there is a dying star and a companion black hole as they orbit around each other. My question is what will possibly happen to the black hole if the partner goes ...
7
votes
6answers
122 views

Determine the moons of Jupiter through a telescope

I was doing my own "space exploration" last night with a telescope. Being a space noob I can't visually determine stars or planets (I know the moon, though), but I focused on one particularly bright ...
4
votes
2answers
108 views

Would a tablespoon of a neutron star remain intact?

I've heard people say that a tablespoon of neutron star would weigh over a billion tons. If we ever could take a tablespoon of one would it still remain intact with the same density?

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