|
The Sun--a diamond in the sky
![[Imagine the Universe, NASA] Sun’s evolution: now to red giant to white dwarf](2002-08-02-white-dwarf.jpg) Q: When our Sun turns into a white dwarf, what will it look like from Earth? --William H., Albuquerque,
New Mexico
A: Soon after the Sun becomes a white dwarf star, about five billion years from now, a creature would see, in
the daytime sky, a shimmering white star of a Sun shining about as brightly as the Moon does now.
[Imagine the Universe, NASA] Sun's evolution: now to red giant to white dwarf
The Sun will have collapsed a million fold to an Earth-size body. Earth's daylight then will be a little brighter
than a Full Moon's light is now--an eerie light with harsh black shadows.
"While the weak light from our almost-dead Sun will permit a human to read a newspaper, it won't provide
much energy to our planet," says Harry Shipman, astronomy professor at the University of Delaware in Newark.
The light will illuminate a totally frozen, oceanless, airless landscape. Slowly, as the Sun cools still more, the
brightness will dim and the color of the white-dwarf dot will change from white to yellow, red, and finally black when it is as cold as
space.
A couple of billion years before that, our Sun will expand into a red giant star whose fiery surface will engulf all planets out to maybe
Earth. If Earth hangs in, her atmosphere and oceans will surely boil away and her rocks will melt into red-hot lava. All life dies as she
cools with the shrinking Sun.
(Answered Aug. 2, 2002)
Further Surfing:
Shipman, U of Delaware: Our Sun's demise
Harvard U, The Sun
Royal Observatory Greenwich, White dwarfs
|
