Transcript Stars

JAXA/SAO/NASA/NAOJ
Trish Jibben
Smithsonian Astrophysical Observatory
Cambridge,MA
Astronomy Picture of the Day (February 21, 2007)
What are Stars?
• Balls of gas burning
billions of miles
away…
SOHO (NASA)
EIT (NASA)
MDI (NASA)
EIT (NASA)
B
o
r
n
Grow
Old
M
i
d
d
l
e
A
g
e
Stars change as they get older Just like
people
But they change
Slowly…
MDI (NASA)
B
o
r
n
Grow
HST (NASA)
Old
M
i
d
d
l
e
A
g
e
Stars are different sizes
White Dwarf
Stars are Hot!
• The color of a star tells you how hot
they are.
Hot
Cool
Hottest stars can get to be
90,000 degrees fahrenheit!
Cool stars are about 5,000 degrees Fahrenheit
Astronomy Picture of the Day July 20, 2006
Some stars are close together
HST (NASA)
HST (NASA)
Some stars that look close are really far apart
Some are VERY close!
HST (NASA)
Stars are moving!
Stars Rotate
Stars move through space
but it takes a long
Time to see them move
QuickTime™ and a
Video decompressor
are needed to see this picture.
XRT (JAXA/SAO/NASA/NAOJ)
Why do stars look like dots?
Close up the statue of liberty looks big!
If you move away from it. It begins to look
smaller…
Hellicopter
Airplane
Stars look like small dots
because they are very, very,
VERY far away.
Space Station
The sun is brightest star in the sky -because we
are close.
Because we are so
close to the sun the
light is really bright
and fills the whole sky
up with light! Daylight!
SOHO (NASA)
Questions
• What would the sun look like if it were
far away?
• What would stars look like if they were
close?
• Because the sun is so close we have to
use special telescope to see it.
• Because other stars are so far away we
have to use telescopes to see them too!