conditions for life on earth Flashcards
how many planets are in our solar system?
9
what is the distance between the sun and the earth?
149.6 million km
how many galaxies are there in the observable universe?
200 billion
how many plants does the universe contain?
10 to the power of 24
what is one main feature of the earth?
it is the only planet that can sustain life
how far away is the nearest earth-like planet?
4.2 light years away
what is the oder of the planets from the sun?
-sun
-mercury
-venus
-earth
-mars
-jupiter
-saturn
-uranus
-neptune
-pluto
what does newtons law of gravity state?
that one object with a mass is attracted to another
define gravity?
a force that keeps objects in place on earth
what is the value of the force of gravity?
around 9.8 ms-2
what happens as the gravitational force increases?
the mass of an object also increases
how was the mass of the earth calculated?
with newtons law of gravity
what is the formula for newtons law of gravity?
F=GmM/r(squared)
who calculated the constant of proportionality?
Henry Cavendish in 1798
what is the formula of newtons second law of motion?
F=ma
who was acceleration due to the force of gravity on earth determined by?
Galileo
who first calculated the radius of the earth?
the Greek Eratosthenes, around 230 BCE, by comparing shadows
what is the formula to calculate the earths mass?
F=GmM/r(squared)=ma
what qualities does water have?
-hydrogen bonds, giving the water molecule stability
-takes a lot of heat to raise the temperature
-it is a good solvent
-it is ideal for metabolic reactions to take place in
what temperature does water freeze at?
0 degrees Celsius
what temperatures does water expand between?
0 and 4 degrees celsius
what temperatures does an enzyme denature?
above 40 degrees celsius
what is the proper name for the atmosphere?
the spheroidal gaseous envelope surrounding the earth
what happens in the atmosphere?
molecule move about randomly and collide with each other, producing pressure
what is the SI unit for pressure?
pascals, Pa
the pressure decreases as we climb up into the atmosphere until it becomes very low, why is this?
because the heavier molecules of the atmosphere are lower down and there are fewer molecules per unit volume
what is the troposphere?
the lowest level of the earths atmosphere and its height changes according to temperature and contains almost all weather
what is the stratosphere?
the layer above the troposphere and the temperature remains constant until we reach about 20km then it increases
what is the stratopause?
the boundary between the stratosphere and the next layer,. the mesosphere
what is the tropopause?
boundary between the troposphere and the stratosphere, it is where the temperature ceases to fall as height increases
what is the main atmospheric gas?
oxygen, O2
at approximately 40-60 degrees latitude there is a marked change what are these known as?
folds
what is the mesosphere?
the layer above the troposphere and the stratosphere
what is the thermosphere?
the upper limits of the atmosphere
as we reach the upper boundary of the mesosphere and move into the thermosphere, we pass into the what?
ionosphere
what is the ionosphere?
an area which contains ions and they are electrically charged and can absorb UV radiation