# Questions tagged [estimate]

Questions asking for approximate results by making an educated, reasonable guess based on the information given.

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### Size of the Unobservable Universe

If you search that question on Google, the answers will be "250 times the size of the observable universe" or "more than 15.000.000 the size of the observable universe". Both of ...
1k views

### How do I estimate the difference in the speed of time flow between Earth and a distant star?

I can use data from Gaia Mission to estimate radial velocity(from RVS) and proper motion(from parallax), to take into account special relativity. The remaining question is what data should I use to ...
• 223
1 vote
33 views

### Magnitude difference between companion in binary from mass difference in binaries

Is there any hypothesis on how to estimate the difference between visual magnitudes of binary components based on their masses? Thank you
• 505
1 vote
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### What is the period of Gamma Cassiopeiae?

Gamma Cassiopeiae is a variable star whose magnitude changes between 1.6 and 3. On what timescale does it vary? The Wikipedia page says that it is irregular, but what is the timescale of its ...
• 17.5k
2k views

### How long between the moment a meteor is first visible and the moment a meteorite hits the ground?

A meteor is usually only visible for a couple seconds at most, but I would guess that it usually stops being visible high above the ground. Meteors often don't make it to the ground as they completely ...
• 17.5k
57 views

### How scientists estimated the number of near-Earth supernovae over the last 11 million years?

According to this article on wikipedia, An estimated 20 supernova explosions have happened within 300 pc of the Earth over ...
110 views

### Photometric redshift - empirical methods (machine learning)

I am currently learning about estimation of photometric redshifts with machine learning methods (or empirical methods in general). These methods use the knowledge about the photometry and the ...
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119 views

### 3C273 jet mass estimate

In this picture of 3C273, we can see a jet—estimated to be around 200,000 light-years long—being emitted. I'm trying to find an estimate for the mass of the jet. It's a stream of ...
• 2,498
50 views

### In SETI has anyone calculated an estimate of the mean time between observations?

So the Drake Equation, proposed by Frank Drake, is often cited as a means to estimate the number of intelligent civilizations that exist in the observable universe. Initial calculations by Drake ...
• 121
203 views

### How did Batygin estimate when Planet Nine was ejected?

Konstantin Batygin has estimated that if Planet Nine was ejected, it would have been ejected 3-10 million years after the formation of the Solar System. I'm curious as to how he arrived at this ...
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1 vote