SPACE-THE FINAL FRONTIER
WHAT IS OUTER SPACE?
• Begins at the end of the Earth’s atmosphere
• About 100Km from the surface
• Called the Kármán line
• Space is a vacuum
• An area that has very little matter
• Only a few hydrogen atoms per cubic meter
• Our atmosphere has 6.02x10^25 atoms per
cubic meter of air
DISTANCES IN SPACE
• Distance from the Earth
• The Moon is 385,000km away
• Venus is 41,400,000km away
• Mars is 78,300,000km away Earth
• Mercury is 91,700,000km away
• The Sun is 149,600,000km away
• Jupiter is 624,400,000km away
• Saturn is 1,250,000,000km away
• Uranus is 2,720,000,000km away
• Neptune is 4,350,000,000km away
China is
11,000km
from Virginia
9.5 diameters
Moon
ASTRONOMICAL UNITS
• Because planets are so far apart, scientists
do not use km to measure the distances
• Use Astronomical Units (AU)
• The distance between the Earth and the
Sun
• Approximately 150,000,000km
• Only used for objects in our solar system
Planet
Distance from the Sun in AU
Mercury
0.39 AU
Venus
0.72 AU
Earth
1.00 AU
Mars
1.52 AU
Jupiter
5.20 AU
Saturn
9.54 AU
Uranus
19.14 AU
Neptune
30.06 AU
DISTANCES IN SPACE
• Stars
• The closest star- Proxima Centari is
39,900,000,000,000km away
• The furthest known star is about
11,000,000,000,000,000,000,000,000km
away
LIGHT YEARS
• To talk about the distances between stars,
scientists use a different unit- the light year
• Equal to the distance light travels in one year
• About 9.5 trillion (9,500,000,000,000) km
• Proxima Centari is about 4.35 light years
away from Earth
STUFF IN SPACE
• Star-a sphere of plasma
held together by gravity
• First catalogued by the
Egyptians (1534BC)
• Were grouped by
constellations by Egyptian,
Greek, Chinese and Arabic
astronomers
STUFF IN SPACE
• Nebula-huge clouds of
dust, hydrogen and
helium
• Can be the beginning
of a new solar system
• Can also be the
remains of a solar
system
STUFF IN SPACE
• Galaxy-a group of stars,
nebulae, dust that revolves
around a center point
• Small galaxies have about
10,000,000 stars
• Large galaxies have about
100,000,000,000 stars
• Have supermassive black
hole at the center
STUFF IN SPACE
• Universe-all of the known matter and energy
• Observable universe is a sphere about
47 billion light years in diameter
• Contains about 3x10^23 stars
• Contains about 100 billion galaxies
• Seems to be expanding all the time
STUFF IN SPACE
• Planetary System-a set of non-stellar
objects in orbit around a star
• Objects may include: planets, moons,
asteroids, comets, dwarf planets
• The ‘Solar System’ is the specific Planetary
System where the Earth is found
STUFF IN SPACE
• Planets-objects in orbit around a star that
have the following characteristics:
1. Is in orbit around a star
2. Has enough mass that it makes a
relatively round shape
3. Does not have significant debris in the
orbital path
STUFF IN SPACE
• Moon-an object that is in orbit around a
planet
• Earth has only 1 moon
• Jupiter has about 67 moons