php require("/home/jeffery/public_html/astro/sun/sun_structure_cutaway_cooling.html");?>
Caption
:
The
structure
of
Sun
shown in a
diagram
with a
cutaway
.
Features:
For a full description of this
diagram
, see
sun_structure_cutaway.html
.
Since the
Sun
is emitting
electromagnetic radiation (EMR)
continuously, it would cool off relatively rapidly if
heat energy
(properly
internal energy
) weren't continually being resupplied.
The cooling off time is long by the time scale of
human
existence---about 2 Myr to end
life
on
Earth
--see, e.g.,
If fusion in the Sun suddenly stopped, what would happen?
---see also
Lord Kelvin's (1824--1907)
estimated
Sun's
cooling time since the formation
Formation of the Solar System
of ∼ 20 Myr (
Wikipedia: Lord Kelvin: Age of the Earth: geology and theology"
)---but short by the
geological time scale
---the
age of the Earth = 4.54(5) Gyr
known
accurately/precisely
from
radioactive dating
---and scale of
cosmic time
---the
age of the universe = 13.799(21) Gyr
known from the
concordance model
which at present seems a pretty good
cosmological model
and fits all observations quite well.
Credit/Permission:
©
User:Kelvinsong
,
2012
/
Creative Commons
CC BY-SA 3.0
.
Image link:
Wikipedia
.
Local file:
local link: sun_structure_cutaway_cooling.html
.
File:
Sun file
:
sun_structure_cutaway_cooling.html
.