If something happens on the sun today, for example an explosion, will we see it with the naked eye only in a million years?
And if so how come? Because light only takes 8.5 minutes to get here, why do we only see it happening over such a long period of time and not within a few minutes?
Asker: Jannick, 21 years old
Answer
The Sun as we perceive it on Earth is the Sun from 8 min 20 sec ago. That is the time it takes for light to travel from the Sun to us.
This is much less than the ‘millions of years’ it takes for light from some stars to reach us, simply because these stars are much further away from us than the Sun.
As an example:
- the Sun is 150 million kilometers away from Earth
- the next closest star, Proxima Centauri, is 4.22 light-years from Earth, meaning that the light from this star only reaches us after 4 years and 3 months
If there is now an explosion on the sun (for example a solar flare, that happens regularly) then we see the first flash 8 minutes and 20 seconds later. The first (high-energy) particles only reach us after about half an hour, because they move slower than the speed of light. Most of the flung material (the ‘coronal mass ejection’) reaches us after a few days. This speed of this material is much slower than the speed of light but still reaches a value of hundreds to thousands of kilometers per second.
Answered by
dr. David Berghmans
solar physics, astrophysics
Royal Observatory of Belgium
Avenue Boechout 10 1020 Brussels
http://www.astro.oma.be/
Avenue Boechout 10 1020 Brussels
http://www.astro.oma.be/
.