The other thread on COSMOS is sequential. People describe latest show. This goes back to earlier shows. And captures highlights.
Watched 5th show. The number of atoms in our body is one billion raised to 3. Greater than number of stars in the known universe.
The number of molecules we breath in each time also greater than no of stars in universe.
Re: COSMOS khichdi/highlights/revision/cheat sheet.
We all know what a tardy grade is. 1 billion tardy grades per Human. They pre existed dinosaurs. So earth is the tardy grade planet.
The photons in the sunlight that hits us today started their journey 10 million years ago. Before humans existed.
The earliest microwave (image?) of the universe is a few hundred thousand years after the big bang. This is just a few minutes into the cosmic calendar.
Sun is hot enough only to fuse hydrogen. There r other starts that fuse helium into other atoms.
Re: COSMOS khichdi/highlights/revision/cheat sheet.
Another reason for this thread - OP of competing thread is a stickler for staying on topic.
Re: COSMOS khichdi/highlights/revision/cheat sheet.
Watched an older show. April 23 I think.
Show was abt determining earths age. Someone had determined it to be exactly 4500 years old birth on Saturday based on some old testament I think. The following I forget names.
.A prof hamilton i thi k hired a Grad student Patterson to measure uranium and lead in zirconium. Uranium was trace. Grad student b measured uranium. Repeatable results. Patterson pb was inconsistent. Contamination. Finally measured it in clean room. Then measure lead and uranium content from meteorite. And Calculated earth age go be 4.5 billion yrs old.
Re: COSMOS khichdi/highlights/revision/cheat sheet.
Show didn't give details. Which is a shame.
We know half life of uranium and other intermediates on way to lead. Which is stable.
So if C_ur_f is ur amt of uranium measured now. And c-pb-f is amt lead. How the heck to determine how much uranium we started with. Unless we assume amt of lead in meteorite was 0 at start. Then we attribute all lead to uranium. Then with uranium measured we may be able to date the earth. Not sure. Disappointed in such details being left out.
Re: COSMOS khichdi/highlights/revision/cheat sheet.
Rome had lead plumbing. Plumbing comes from plumbum Latin for lead. Slaves used to mine lead. Died.
Fast forward 20th century. Petroleum industry added lead additive. Even though they know lead was poison. Patterson fought them 20 years.
He found lead conclusion in shallow water lower tha. Deep ocean. So surface contaminatioj..Went to arctic. Got ice from pre industrial time. Lead conclusion lower. Proved lead higher conc is due to fuel. Oil lobby hired scientist.to testify lead is not causing problem. Finally food science won over rogue.science.
Re: COSMOS khichdi/highlights/revision/cheat sheet.
.A prof hamilton i thi k hired a Grad student Patterson to measure uranium and lead in zirconium. Uranium was trace. Grad student b measured uranium. Repeatable results. Patterson pb was inconsistent. Contamination. Finally measured it in clean room. Then measure lead and uranium content from meteorite. And Calculated earth age go be 4.5 billion yrs old.
Sorry for cutting and pasting off Google, but this explains in a much better and simpler way.
As Patterson explained in an interview in the year that he died, the Canyon Diablo meteorites didn't contain any uranium, a metal that radioactively decays into lead at well-established rates taking hundreds of millions of years. Other rocks contained both lead and uranium.
So, by reporting the ratio of lead types found in these pristine meteorites and comparing them to lead ratios found in the other rocks on the Earth and other meteorites, Patterson could calculate the age of the solar system, when the Earth formed, to be 4.55 billion years old, give or take 70 million years.
Re: COSMOS khichdi/highlights/revision/cheat sheet.
Sorry for cutting and pasting off Google, but this explains in a much better and simpler way.
As Patterson explained in an interview in the year that he died, the Canyon Diablo meteorites didn't contain any uranium, a metal that radioactively decays into lead at well-established rates taking hundreds of millions of years. Other rocks contained both lead and uranium. So, by reporting the ratio of lead types found in these pristine meteorites and comparing them to lead ratios found in the other rocks on the Earth and other meteorites, Patterson could calculate the age of the solar system, when the Earth formed, to be 4.55 billion years old, give or take 70 million years.
I think cutting and pasting Google is a good way. No issues.
What is Canyon Diablo meteorite. Is this the pristine meteorite Patterson tested. So which means all had converted to pb. But we don't know when it happened. So how to calculate age.
What is meant by ratio of lead types.
Re: COSMOS khichdi/highlights/revision/cheat sheet.
Yes Cannon Diablo Meteor is the one he tested.
The meteor had zero uranium, which means all converted into lead.
The zirconium that he tested had both uranium and lead. Half life of uranium is known, which means the amount of time it takes for 50% of any given amount of uranium to decay into lead. Half life means that if we start with 1 kilo of uranium, then in X number of years, it will become 1/2 kilo where other 1/2 kilo will decay into lead. It will take the same number of years (X that is) for the remaining 1/2 to turn into 1/4 kilo. Same number of years to 1/4 to 1/8 kilo and so on.
So if we see find a rock on earth, and look at the amount of uranium and lead, then by using the half life equation, we can back calculate the time where full uranium was there and no lead was present. That is when the rock was formed, hence that is when the earth was formed.
Re: COSMOS khichdi/highlights/revision/cheat sheet.
Ok. My peeve was he didn't mention when earth was formed there was no lead.
Also pristine meteorite had no uranium. So all had converted to lead. But we don't know when. All we know is if it got converted today earth is 4.5 billion years old. But if it got converted 2 billion yrs ago earth is 2 plus 4.5 or 6.5 billion yrs old.
Good question. I was also thinking the same thing. Need to read more in detail of his work to understand that part.