A Quick Tour

A Quick Tour
The distance between
Baltimore and
Washington is
roughly 60 km.
Let’s make a new
unit of
measurement called
a BW where,
1 BW = distance
Washington and
Earth - Diameter about 13,000 km or 213 BW
Earth’s Moon – about 380,000 km away or
6,400 BW
The Inner Solar System (Sun, Mercury, Venus, Earth,
Mars) – about 3 Astronomical Units (AU) or 450
million km across or 7.5 million BW
The Solar System out to Pluto’s orbit 80 AU or about
12 billion km across about 200 million BW
Nearest 25 stars enclose a region about 26 light years or
2.5 x 1014 km across 4 x 1012 BW = 4 trillion BW.
Our “neighborhood” within a spiral arm of the Milky Way Galaxy –
a few kpc or about 9 x 1016 km about 1.5 x 1015 BW.
The Milky Way is about 100,000 light years or 30 kilo
parsecs across. This is about 1.5 x 1016 BW.
The nearest galaxy
similar to our own
Milky Way Galaxy is
the Andromeda
Galaxy. It is 670 kpc or
about 2 million light
years away. This is 3.4
x 1017 BW.
Our galaxy and
Andromeda belong to a
cluster of about 30
galaxies called the
Local Group about 3
million light years
The Local Group is a member of the Local
Supercluster about 30 mega parsecs or 100
million light years across.
The most distant
object observed
is a supernova
roughly 10
billion light
years away or
about 1 x 1021