So, I'm doing a report for physics, and I have been presented with a question...

What was the early atmosphere of the Earth like? As I understand it, the early atmosphere was without oxygen, to allow the development of life. Is this still the prevalent school of thought? What was it like? Was the Earth's atmosphere really as hellish as it sounds?

Any imput would be very welcome. The report is due at the end of this week, today being Monday.

Although there is some debate as to the nature of the early earth, if one looks at the possible volatiles on the surface of the earth, one can deduce that the early atmosphere of the earth contained plenty of water and carbon dioxide. The water became the oceans and the carbon dioxide became mineral and dissolved carbonates (limestone).

Secondary or earlier possibilities would also include chlorine gas due to the high concentration of sodium chloride found in the oceans. Chlorine gas is a strong oxidizer and could form molecule nitrogen and oxygen, to create the choride anion or Cl-. It is also likely that there was hydrogen gas. This would account for all the H in H2O. The hydrogen would also be associated with carbon as methane and other light volatile hydrocarbons and to nitrogen as ammonia.

The oxygen from chloride reduction would react with the hydrogen, methane and ammonia to form water, carbon dioxide (carbonates) and nitrous oxides (nitrates). When the reaction potential within the atmosphere lowered, the nitrates and carbonates could eventually be reconverted to the observed nitrogen and oxygen atmosphere via the living state. This reversal of potential came from the sun.

besides chemicals in the atmosphere. I might add that possibily since we add a second to the atomic clock the Earth rotated faster. And instead of a 24 hour day- Earth had maybe had a 20 hour day.
And Gravity might have been different- Stronger maybe.
And if that's true then dinosaur's might have been even stronger then we realize.
A T-Rex running at 37 miles an hour then, might be 45 mph today.
60 million years from now we might be walking on air. well anyway...

In fact you are mostly right...

Life could not have evolved with the presence of Oxygen, that is very important.... all early life was anaerobic because of the toxicity of Oxygen to all life.

But... that doesn't mean Oxygen wasn't being produced, it was, but with so much Iron around all the Oxygen for billions of years, simply reacted withall that Iron to form various Iron Oxides, as can be found all over the world.