The drilling technique known as is causing much controversy in drilling oil shales.
panning
scrubbing
fracking (hydraulic fracturing)
horizontal drilling
which of these elements may be the fuel of the future?
oxygen
hydrogen
helium
carbon
ohio has a lot of coal. what grade is it?
lignite
anthracite
bituminous
sub-bituminous
in ohio, the entrances to abandoned underground mines are cleaned and barred so can live in them.
ground hogs
bats
raccons
moles
as the solar system was forming, came closest to undergoing nuclear fusion and becoming a second sun.
neptune
earth
jupiter
saturn
the sun, its eight planets and their moons, together with smaller objects such as asteroids and comets, form the
milky way
oort cloud
kuiper belt
universe
solar system
the discovery that the universe appears to be expanding led to widely accepted cosmological theory for the formation of the universe called
the big bang
hubble’s law
einstein’s law
the doppler effect
to measure distances in our solar system, astronomers use the which is the earth’s average distance from the sun.
parsec
astronomical unit (au)
light year
click
mega-kilometers
our galaxy is called the
oort cloud
kuiper belt
asteriod belt
milky way
solar system
possibly the most cataclysmic event to occur in the universe is
an asteroid impact
a supernova
hydrogen burning
to the best of our knowledge, the earth, sun and moon are all the same age, about years old.
4.6 billion
4000
500 million
1 billion
100,000
is the largest planet in both radius and mass.
mercury
earth
jupiter
venus
mars