8 Answered Questions for the topic observational astronomy

Observational Astronomy Astronomy


View of the Sun from Voyager 1?

Today Voyager 1 is approximately 122 AU distance from the Sun. What does the sun look like from this distance? How much brighter does the sun appear to the naked eye compared to other stars in... more
Observational Astronomy Astronomy Stars Universe


How do we estimate $10^{23}$ stars in the observable universe?

Now, I read somewhere, that there are 4,106,234 stars in the observable universe. How did scientists estimate this?
Observational Astronomy Astronomy Solar System Telescopes


Can any telescope be used for solar observing?

Can any telescope, such as a 8" reflector, that is normally used at night to look at planets be used or adapted for solar observing?What kind of adapters or filters are required or is it better to... more
Observational Astronomy Astronomy Telescopes


Why is the Hubble Space telescope able to see farthest in the universe?

What determines how far a telescope can see in the universe? How does recording data for a very long time (~10 years) help? If we could build a telescope which work at microwave region, will it be... more
Observational Astronomy Astronomy Galaxies Milky Way


Did I see two Milky Ways next to each other?

I am from the northern hemisphere and as far as I remember, the Milky Way was "single lane", just one stripe. At least, this is what I recall the Milky Way to look like when seeing it from near... more
Observational Astronomy Astronomy Stars Visible Light


Why do stars flicker?

Why do stars flicker and planets don't? At least this is what I've read online and seen on the night sky. I've heard that it has to do something with the fact that stars emit light and planets... more
Observational Astronomy Astronomy General Relativity Cosmology


What is the most compelling evidence of General Relativity in the presence of matter and energy?

The most oft-cited [triumphs](http://en.wikipedia.org/wiki/Tests_of_general_relativity) of GR are things such as the shifting perihelion of Mercury, gravitational redshift experiments, and... more
Observational Astronomy Astronomy General Relativity Cosmology


What are the different ways to measure the spatial curvature of the universe?

Just what the question asks. Assuming the Friedmann-Rovertson-Walker (FRW) metric, what measurements can be performed to determine the spatial curvature of the universe.

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