Tag Info

New answers tagged

0

The simple answer is that atmospheric refraction makes the disk of the sun visible at sunrise or sunset, when it's actually half a degree or so below the horizon: In reality, both the extent of refraction of the sun's disk and the refraction of the apparent horizon come into play. Both depend on the atmosphere's density and temperature profile; which ...


1

I would go to the Arctic circle, where you can experience an almost perpetual sunset, without having to drive around. Edited to answer the question: My interpretation of the diagram, is: The terminator at a certain time near sunset, is the one shown towards the east (darkness approaches), running NE/SW. As time progresses, it moves into the top horizontal ...


0

It ends at that distance at which objects are, for all practical purposes, no longer bound to the solar system barycenter. This is usually defined by the Hill Sphere, which approximates the gravitational sphere of influence. One simple view of the extent of the Solar System is the Hill sphere of the Sun with respect to local stars and the galactic ...


5

As HDE 226868 noted in his answer, the Sun is not going to go supernova. That's something only large stars experience at the end of their main sequence life. Our Sun is a dwarf star. It's not big enough to do that. It will instead expand to be a red giant when it burns out the hydrogen at the very core of the Sun. It will continue burning hydrogen as a red ...


6

The Sun does not have nearly enough mass to become a supernova. Instead, it will swell to become a red giant, enveloping Mercury, Venus, and possibly Earth. After that, it will shed its outer layers as a planetary nebula, and settle down to become a white dwarf. Wikipedia, apparently, says the exact same things I had though of: The Sun does not have ...


2

The degree of ionization in the photosphere varies with depth of course, but overall it is small. Table 1 of the Bilderberg Continuum Atmosphere (Solar Physics, 3, 5, 1968) gives the pressure and the electron pressure at various optical depths in a comprehensive model. The ratio of the pressure gives the Ne/Ntotal. At optical depth = 1 at 5000 ...


-2

For our planet to exist, for us to exist, a star would've had to have exploded to create the heavy elements (those greater than Iron on the periodic table) to generate the high temperatures needed to create those elements. ( https://www.universeguide.com/fact/planet ) . Therefore Sun could've been a binary star system. So where are they now? We're from ...


3

Most stars form in clusters, so it is very likely that the Sun was part of a star cluster when it formed. But in On the Dynamics of is Open Clusters, the relaxation time of a cluster is calculated to be in the order of $\tau=4\times10^7 \textrm{yr}$. During that time about one hundredth of the stars will escape from the cluster (i.e. reach escape ...


2

It is generally believed they have drifted relatively far away in the 4.5 billion years since the Sun was formed. Astronomers recently identified a candidate for one Solar sibling that is now 110 light years away: http://www.skyandtelescope.com/astronomy-news/sun-sibling-found/


1

These steps are in there for credit I used Stellarium to simulate a sunrise, and took screenshots of the progression. Each screen shot was 2 seconds apart, and stellarium was accelerated to 10 minutes a second. Then, using imagemagik to crop batch those 13 images with this command: mogrify -crop 1280 1024 *.png (those numbers are the size of my screen. ...



Top 50 recent answers are included