How old is Earth
The clock used for measuring the geological age of the earth
Is a nuclear clock.
The most common is called U238 pb206 clock. U238 has a half life of 4.51 billion years.
After a long chain of decays the end element is pb206 and U238 in an old rock. This would tell us how long the uranium has been decaying in that rock that gives us the age of the rock.
This has been done very carefully. Some other radioactive dating methods have also been used.
The current consensus is that the age of the earth and the solar system is 4.6+0.1 or 4.6-0.1 billion years.
The most common is called U238 pb206 clock. U238 has a half life of 4.51 billion years.
After a long chain of decays the end element is pb206 and U238 in an old rock. This would tell us how long the uranium has been decaying in that rock that gives us the age of the rock.
This has been done very carefully. Some other radioactive dating methods have also been used.
The current consensus is that the age of the earth and the solar system is 4.6+0.1 or 4.6-0.1 billion years.
Weight of earth
Since the earth is suspended in space,"weighing" it is not the same thing as putting an object on a scale.
when we speak of the weight of the Earth, we mean the amount of matter that makes it up.
this is called its mass.
The earth's mass is about 6600 trillion tons. to give you an idea of how that number looks here it is ----
66 00000000000000000000 .
how did scientist find out that this was the mass of the earth,?
To do this, they used a principle based on the fact that any two objects attract each other.
this is what the force of gravity depends on. put in simple terms, the law of gravity states that two objects are attracted by force That depends on their mass and their distance apart .
the bigger the objects the greater the force that pulls them together . the farther apart they are, the smaller the Force.
To measure the weight of the Earth, the following is done- a small weight is suspended from a string .the exact position of that weight is measured .
now a tonne of lead is brought near the Hanging weight. there is an attraction between the weight and the lead and this causes the weight to be pulled just a tiny bit out of line . actually it is less than 0.00002 mm so you can see how carefully the measuring must be done.
After this is measured scientist can use mathematics to figure out the weight of the earth.
they have measured the power of the earth's attraction on the weight and they have measured the power of the 1 ton leads attraction on the suspended weight.
the relative difference can be calculated and tells them the mass of the earth.
What is this mass made of?
There is the crust of solid rock ; then a layer called the Mantle which is also solid Rock and goes down about 1800 miles ; and then the innermost part, which is the core and is about 2100 miles in radius . the material of the core is liquid because of the great heat at the centre of the earth.
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when we speak of the weight of the Earth, we mean the amount of matter that makes it up.
this is called its mass.
The earth's mass is about 6600 trillion tons. to give you an idea of how that number looks here it is ----
66 00000000000000000000 .
how did scientist find out that this was the mass of the earth,?
To do this, they used a principle based on the fact that any two objects attract each other.
this is what the force of gravity depends on. put in simple terms, the law of gravity states that two objects are attracted by force That depends on their mass and their distance apart .
the bigger the objects the greater the force that pulls them together . the farther apart they are, the smaller the Force.
To measure the weight of the Earth, the following is done- a small weight is suspended from a string .the exact position of that weight is measured .
now a tonne of lead is brought near the Hanging weight. there is an attraction between the weight and the lead and this causes the weight to be pulled just a tiny bit out of line . actually it is less than 0.00002 mm so you can see how carefully the measuring must be done.
After this is measured scientist can use mathematics to figure out the weight of the earth.
they have measured the power of the earth's attraction on the weight and they have measured the power of the 1 ton leads attraction on the suspended weight.
the relative difference can be calculated and tells them the mass of the earth.
What is this mass made of?
There is the crust of solid rock ; then a layer called the Mantle which is also solid Rock and goes down about 1800 miles ; and then the innermost part, which is the core and is about 2100 miles in radius . the material of the core is liquid because of the great heat at the centre of the earth.
Liked the above article click for more like this.
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