How Big Are Things? Home     Welcome	small		Real world	big			solar system		between	galaxy
	nano	micro		meter	kilo		Mega	Giga	Tera	Peta	Exa

Tm = 1012 m

look at a sheet of graph paper

galaxy		21
		20 19
local stars		18
		17 16
between		15
		14 13
E's orbit		12
		11 10
sun		9
		8 7
texas		6
		5 4
hood		3
		2 1
you		0
		-1 -2
salt grain		-3
		-4 -5
bacteria		-6
		-7 -8
atom		-9

All alone in the night...

Heliosphere and bow shock

light-Megaseconds ( 106 lt·s )
0	1	2	3	4	5

light-year
0	0.1	0.2

src a small planetary nebula Size is only approximate. False color.

A planetary nebula represents the final stage in the evolution of a star similar to our Sun. The star at the center of IC 418 was a red giant a few thousand years ago, but then ejected its outer layers into space to form the nebula, which has now expanded to a diameter of about 0.1 light-year. The stellar remnant at the center is the hot core of the red giant, from which ultraviolet radiation floods out into the surrounding gas, causing it to fluoresce. Over the next several thousand years, the nebula will gradually disperse into space, and then the star will cool and fade away for billions of years as a white dwarf. Our own Sun is expected to undergo a similar fate, but this will not occur until some 5 billion years from now.

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