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1answer
65 views

How to calculate local position, knowing the RA and Dec of the center of an image, RPY of the camera, and precise time?

Given a picture of stars - assume it is possible to identify the stars and their Right Ascension (RA) and Declination (Dec). By choosing one near the center of the image (or interpolating RA/Dec to ...
3answers
55 views

If the Sun disappears right now, when the absence of its gravity affects on Earth?

Imagine if the Sun disappears right now. When the Earth will be affected by its absence? Does it affect immediately, or it takes almost 8 minutes? (The time that light travels from the Sun to the ...
2answers
96 views

Age of Jezero crater on Mars

How long ago the Jezero crater was formed on Mars? And is it a meteorite impact crater?
3answers
4k views

Why are stars so far apart?

So, this is mere musing, but it seems that stars are quite extremely far apart. I tried to determine the mean distance between nearest neighbors for stars (in just our galaxy) but I'm not sure what it ...
0answers
6 views

Deep-CEE I data

I was reading the Deep-CEE I and I couldn't find the dataset. Could someone provide me with the links related to this?
3answers
665 views

Why are stars still distant from one another? [duplicate]

Why are stars so far from each other? Shouldn't gravity pull them closer over time? And if the effects of gravity are negligible is there an explanation why stars have to be so distant from one ...
1answer
51 views

1answer
382 views

Is there permanent dry ice on Mars?

Are there any places featuring permanent dry ice (carbon dioxide ice) on Mars? Is there dry ice at the poles?
1answer
76 views

Kardashev scale [closed]

Why is becoming a type 3 from a type 2 civilization the hardest? I have watched many videos on the topic and still can't figure out why? Also is there a difference in technology between a type 4 and a ...
1answer
197 views

What are the Mathematical Algorithms/Formulas behind hindu Sunrise and Sunset Calculations?

There are differences between Astronomical Sunrise/Sunset calculation and Hindu calendar Sunrise/Sunset calculations. The astronomical algorithms to calculate the sunrise/sunset can be found over the ...
1answer
107 views

Saint-Exupery describes visit to plateau where he easily finds several meteorites. Is this realistic?

In "Wind, Sand and Stars" Antoine de Saint-Exupéry describes a visit to a plateau where it is extremely easy to discern meteorites from stones, since there are no stones. I picked up one ...
1answer
140 views

Why is CMB an evidence of hotter and denser early Universe?

In his book Gravitation and cosmology, Steven Weinberg says that CMB makes it "difficult to doubt that the universe has evolved from a hotter denser early stage". In my understanding, CMB ...
2answers
86 views

Binary Star Initial Speed

I am writing a 2D simulation for binary stars orbiting each other. Currently, the initial position of the stars are on opposite sides of the screen with the left star having a velocity up the page and ...
0answers
158 views

What is the highest resolution camera on a Mars orbiter? [migrated]

The GeoEye-1 satellite has the high resolution imaging system and is able to collect images with a ground resolution of 0.41 meters (16 inches) How about Mars then? From all the Mars orbiter's cameras,...
2answers
3k views

Why does the Fourier transform of this CMB image have a hole in it?

The BBC's Desert telescope takes aim at ageing our Universe contains the image below of the Cosmic Microwave Background from the Atacama Cosmology Telescope or ACT. It looks like this is plotted with ...
2answers
34 views

Corresponding values for the Sun's ultra violet color maps?

In my laboratory, we have an antenna to get data from the GOES-16 satellite and I want to reproduce NASA's nice visualization of ultraviolet images from the sensor SUVI. I can read the data without ...
0answers
39 views

Ice filled craters on Mars

How many craters on Mars have ice in them and which ones have permanent ice? I could only find Korolev and the unnamed one - strange for such a remarkable crater. http://www.esa.int/...
1answer
65 views

How far can we detect lightning in radioastronomy?

The wikipedia article on whistlers has this information: Voyager 1 and 2 spacecraft detected whistler-like activity in the vicinity of Jupiter known as "Jovian Whistlers", implying the ...
1answer
79 views

Puzzle about proper distance

So I tried deriving the radial co-moving coordinate formula to an observable galaxy for which the light observed at time $t_o$ was emitted at time $t_{em}$. i.e $r_0=\int_{t_{em}}^{to} c/a_{(t)} dt$ ...
1answer
48 views

What was the the value of the Hubble constant at the time of the CMB's 'release' (i.e., 379,000 years after Big Bang)?

What about its value roughly 9 billion years after the Big Bang, when dark energy started to 'take over' and accelerate the expansion of the universe? Is there a timeline or chart somewhere that shows ...
0answers
60 views

Radiation and software reliability in outer space [closed]

We all know that dragon was written in c++ but what i struggle to understand is that if radiation in space can really mess with hardware and functionality and even have the capacity to change bits ...
2answers
42 views

How can I get/generate/extract PSF image from galaxy .fits image?

I want to model an image of a galaxy from Hubble. For this, I need the PSF image as well. I already tried to use TinyTim, but I don't have half of the parameters and cant be sure about the quality of ...
0answers
39 views

How significantly does the intensity of a meteor shower diminish after the peak?

Every August 12 I take the family to the desert to enjoy the Perseid meteor shower. This year there will be an especially bright moon rising before 1:00, which is when the shower really peaks. Last ...
1answer
47 views

Kinetic energy and galaxy arm rotation rate

The higher than expected rotational velocity of stars and gas clouds in the outskirts of galaxies is explained today by invoking dark mater that supplies not only the additional gravitational mass, ...
2answers
44 views

Distinction between signal from terrestrial and signals from celestial sources

How is it confirmed that a radiation source (not in visible light) is either terrestrial or celestial? If in-depth explanation and/or references are possible, I would be grateful.
2answers
1k views

When the sun “enters” a constellation, doesn't it make it impossible to see that constellation?

I was reading on NASA's website about how the Babylonians came up with dividing the sky into different slices and picked a pattern of stars in each slice to represent it. This ties in to astrological ...
2answers
2k views
+500

Compute Planet's Apparent Visual Magnitude

In a hypothetical solar system there exist: a sun of radius $r_s$ and absolute visual magnitude $V$ the Earth, with radius $r_e$ and distance from the sun of $1\,AU$ another planet, wit radius $r_p$, ...
3answers
3k views

Is it possible to completely see the edge of a half moon at night?

Some days ago, about 1 ~ 1.5 hours after the sunset I could see a very bright half moon, and the interesting part is, I think I could see the edge of the dark half of the moon, i.e. a whole circle, ...
2answers
3k views

Was this an astronomical phenomenon observed in 1689?

In a Swedish church record from 1689 a phenomenon in the sky is described. With my very limited understanding it could be a meteorological or an astronomical phenomenon, so here I ask if it could have ...
0answers
21 views

Does a rotating moon experience greater tidal heating than a tidally locked equivalent?

Tidal heating of a tidally locked moon is relatively straight forward to calculate, even though details of its internal structure is hard to work out in the first place. By contrast, tidal heating due ...
2answers
66 views

Is there a way to know if there are/are not solar-system-like systems of objects without a star?

There's an extremely high amount of variation in All of Known Existence. We do see many many stars, with an extensive amount of evidence for planets orbiting around stars. However, is there are way to ...
1answer
121 views

Black dot visible when looking into the telescope

a few weeks a go i bought a telescope: The problem is I am a total beginner. I was able to setup the telescope correctly and i already saw the moon very clearly. Then I moved on to jupiter. When I ...
2answers
70 views

Can a single impact event trigger a runaway greenhouse?

Somewhat related to this question: Is the Earth going to evolve towards Mars' fate or Venus' fate? Human civilization may be fragile, but life itself is extremely resilient, with extremophiles and ...
0answers
68 views

What is the true formula for the density of exoplanets? [closed]

On websites, I have seen multiple formulas for the density formula for exoplanets, but what is the most accurate.
2answers
58 views

How to calculate the orbital period and the density of a planetary body?

I'm a student studying in 9th grade, I am making this fictional habitable planet named "Darwin B" for a planet making competition. It orbits a sun-like star at a distance of 1.15 AU or 172 ...

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