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Roughly 550-600 mya (mya=millions years ago) and in the paleozoic era :D
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How did oxygen first appear in the atmosphere?
It is believed that when primitive algae flourished on an early earth, they pumped out zillions of cubic kilometres of this gas. Before them, oxygen wasn't around in the atmosphere in very large quantities. After long, long periods of time, the percentage of oxygen in the atmosphere rose. It is to these early life forms that we owe the "air" and the atmosphere that supports us now.
Is the earth a stationary object in the lunar sky?
No, it is not. This will seem wrong to people who are aware that the moon's orbit it tidally locked with earth. Observed over a long enough period, the moon has a distinct wobble that comes from what is called libration. It results from the fact that the moon's orbital velocity around the earth is not constant, while the moon's rotational velocity is for all practical purposes constant. So the earth will appear to move a bit in the lunar sky. This is an apparent motion and not a true motion. It occurs to me that there must be places on the moon where the earth would appear, over the course of a lunar cycle, unable to decide whether to rise or to set! It would appear to bob up and down at the moon's horizon.
How long has wood been on earth?
forever it was on earth when the earth was made
Why sedimentary rocks could not have been the first rocks on earth?
water is needed, and long periods of deposit of sediment at the bottom, to form the sedimentary rocks. A hot, molton earth could not have created such rocks.
How long have earthquakes been around?
The earth's crust is first thought to have formed around 100 million years after the initial formation of the earth. As such it is likely that there have been earthquakes occurring for approximately 4.4 billion years.
Did sharks appear when dinosaur extinct?
No. Sharks appeared on earth long before the first dinosaurs did.
Where and when did toys first appear?
every since rocks came 2 earth along with mud pies
When did elephants appear on earth?
in the ice age the mammoths were the first elephants
How long ago did mans first ancestor appear?
on the 12th of march
Why does the sun appear the be the brightest star in the sky to us on earth?
because it is the nearest star by a long way
Why do the stars in the night sky appear tinier than the Earth?
Because they are a VERY long way away.
How long have reptiles inhabited the earth?
Reptiles inhabited the earth before dinosaurs inhabited the earth. The first reptiles appear in the fossil record over 300 million years ago, in the Carboniferous period of the Paleozoic era.
When did numbers as we know them first appear?
A Long...Long....Long....Long......Long....Long.....Long...Long.......Long.....Long....Long..Long Time Ago XD
How long ago did the first dinosaurs appear?
About 230 million years ago.
How long ago did dinos start to roam Earth?
Dinosaurs stated to appear 240 million years ago.
Is there really a sponge bob movie 2?
yes, there is going to be a sequel to the sponge bob square pants movie. It'll air after the final sponge bob episode airs on Nick. Supposedly in the movie sponge bob and sandy get married. but that wont be for a long time because sponge bob isn't going away for a long long time
How long has sponge been on tv?
13 years
