The Universe: Life & Death of a Star

The Universe : LIFE & DEATH OF A STAR
History Channel
Season. 01 Episode. 10

http://www.history.com/shows/the-universe
http://en.wikipedia.org/wiki/The_Universe_%28TV_series%29
http://www.youtube.com/watch?v=_OtkgXnMErc


EXCERPTS:

PILLARS OF CREATION
7000 LIGHT YEARS FROM EARTH
EAGLE NEBULA


To form a star like our Sun
which is a million miles across,
it takes a clump of gas and dust
100 times the size of our Solar System.
These clouds start off their lives bitterly cold,
with temperatures hundreds of degrees below zero Fahrenheit.
But as gravity fragments and compresses them,
the heat begins to soar.
[is this explanation equivalent to religious sayings (imam Ali) that Universe is made up of water. Clouds Cold - doesn't resemble to water?!]


"Gravity want to CRUSH the star down to the middle.
For stars, nuclear fusion provides the rope in the form of pressure."
(nuclear fusion of star try to resist this gravity to not be crushed)


"Red Dwarfs are very common in the universe"

"The more massive stars live much shorter lives than the less massive stars."


"it won't be able to fuse that helium into heavier elements,
like carbon and oxygen,
until the core gets sufficiently hot.
And that's because it's harder to get the helium nuclei close enough together
for the strong nuclear force to take over,
grab them, and cause them to fuse together.


"When it reaches 180 million degrees, it can start fusing helium into carbon,
in a desperate gamble to survive."

"The star which took 10 billion years to burn through its hydrogen,
now powers through its supply of helium in a mrere 100 years.

"it runs out of H, starts fusing He,
runs out of He, attempts to fuse C and will fail."


As the star the size of our Sun dies,
it eject its outer layers.
(due to loose gravitational force, and shapes like Planetary Nebula)

"The white dwarf has about 300,000 times the mass of the Earth,
compressed into a volume the size of the Earth.
If you had just a teaspoon full of material, it would weigh several tons."


"The White Dwarf is the final stage in the life of a Sun-like star.
But it's not quite dead yet."


White dwarfs are retired stars, lives billions of years on the energy which they saved in their youth.


Thermonuclear runaway
Type 1 super nova


supernova happens twice in each galaxy per century.


"It goes through its normal life fusing H into He,
then Hel int C and O, then O into Ne and Mg
and then Si and Sulpher.
and then Iron (Fe).


Supernovas are in fact source of heavy elements.

"All the iron you see everywhere came from exploding stars.
And in fact all the elements heavier than iron directly or indirectly were made by
exploding stars."


"If you could trace your ancestry back to its earliest reaches,
you would find an exploding star in your family tree."


"The elements in your body - not generically but specifically -
heavier than H and He,
came from long-dead stars.
The Ca in you bones the O that you breathe,
the Fe in your bloodcells, the C in most your cells...
All those things were created in stars through nuclear reactions.
and then ejected by supernovae."


NEUTRON STAR
"Compared to normal stars, neutron stars are cosmic pebbles.
They can be as small as 10 miles acros.
... extremely dense object.
one teaspoon full of neutron star material would weigh a billion tons."


"Black holes are basically gravity's victory over mass."


"In the fall of 2006,
astronomers observed the largest stellar explosion
ever witnessed by Man.
240 million light years away from Earh,
a massive star blew itself apart.

A normal supernova comes from the explosion of a star
10 times more massive than our Sun.
Incredibly, supernova 2006GY, as astronomers have dubbed it,
seems to have signaled the death of a star
150 or even 200 items more massive."


Fortunately, the chances of this (colliding stars) happening are slim,
because the Sun is in a very uncrowded part of the Milky Way.


"Blackholes, neutron stars and white dwarfs,
all represent the end of remarkable stellar lives."


BROWN DWARF
not quite planets, not quite stars.
"brown dwarfs are basically failed stars."


PROTOSTAR
MAIN SEQUENCE

___________________________

How to Build a Human

How to Build a Human
BBC - 2001

http://www.imdb.com/title/tt0487830/

EXCERPTS:

Part 1 - CREATION
tags: Cloning, Human cloning

 
"This is the 8th day of Creation."

"This vision of future (cloning the parts of human) depends on creating cloned human embryos,
something no one has ever done before.


"Human eggs are precious, because a woman's ovaries normally produce just one egg every month."


"Judson's skill cell, like almost every other cell in his body,
contains all the genetic information needed to build another Judson.


"At the heart of cell lies the nucleus,
protected inside the nucleus are chromosomes,
chromosomes are nothing more than tightly bound packages of DNA.
When they're unraveled the characteristic double-strands of DNA are revealed.
Each strand of DNA carried hundreds of genes.
And its these genes that build everything,
from the shape of your nose to the color of your skin.



"But there are certain human situations where one has lots of sympathy for the people involved.
An example would be where parents have a child who has died or dying,
and they might be tempted to think about reproductive cloning.
So that they could somehow bring that child back to life.
My own personal view is that i really don't think that's a good idea, i really dont."


"Geneticist John Burn thinks such notions are fundamentally flawed.
People often think about cloned humans as sort of huge photocopies.
But of course, they're nothing like that.
If you take and adult cell from and an adult person and create a new embryo,
then you would be producing the same genetic make up,
BUT IN A DIFFERENT WOMB, IN A DIFFERENT GENERATION,
so they would be nothing like as similar as, for example,
identical twins that have formed naturally.

"A clone might look the same, but could never really be the same
because of the influence of the environment.

"We know from looking at identical twins that they're not actually identical.
The outside world will have an influence on how a person develops,
quite apart from their genes.
And it's not just what happens after you're born,
it's also what happens to you in the womb
that will have an enormous impact.
In other words, WE ARE A COMBINATION OF OUR NATURE AND OUR NURTURE."

_______________________

Part 2 - PREDICTOR

_______________________

Part 3 - THE SECRET OF SEX

 
"Understanding the sex is the key to understanding how to build a human."


"The Y has around 60 genes and the eggs around 3,000."
"Y chromosome is the smallest chromosome.
and when you look at it in detail only a very small part of it actually codes for anything.
So most of its a desert.

"Imagine that your DNA was a piece of string,
so you could see it.
So we've magnified the DNA which is present in every cell in your body so it's visible.
And that piece of string now would stretch from here to Moscow.
Now, if we were to start a journey from here to Moscow, on foot,
the Y chromosome would represent the first 20 miles of that journey.
and the SRY gene would be the first step on the journey to Moscow.

It takes 30,000 genes to build a human,
but just one gene - the SRY to build a man.

When the SRY is switched on, it fires up the development of the male sex organs.

the SRY triggers development of the testes, and they produce a very versatile hormone called testosterone."


"If it can't react to testosterone the fetus assumes the default position,
which is female."


"The discovery that men are created from a female blueprint was certainly a big surprise
and contradicts previously held notions about the relative importance of men and women.
 
"the bible was fundamentally the wrong way around. woman was not born of man's rib, its the other way around."

"One very obvious remnant of our female past can be found on every male chest.
Nipples.
The reason men have nipples, is because the developed in foetus before testosterone kicked in.


"Women naturally have some testosterone in their bodies, but men have ten times as much.
And some men have more than others.


"It starts in a womb."
Compare the hand of the man,. with that of the woman..
The man's ring finger is longer than his index finger.
in the case of the woman, it's the opposite;the the index finger is longer than the ring finger.

"We think that the length of the ring-finger is a direct indicator of the amount of testosterone one's exposed to in utero,
and the lenght of the index finger indicated the amount of oestrogen you've been exposed to in utero.
So it's the relative lenghts of these two fingers that are important.
If you've got a longer ring finger than your index finger you have been exposed to high testosterone.
If you've got a longer index finger than ring finger you've been exposed to low testosterone and hig oestrogen."
Dr. John Manning



"But doing it in humans would be a big and disturbing advance.
The differences, on a genetic level, between us and our early ancestor like Australopithecus are tiny, less than 1%.
If it only took a few tiny changes in our DNA to gro from Australopithecus to us,
imagine where implanting an array of artificial chromosomes might lead to."

________________________

Part 4 - FOREVER YOUNG

"Human body is made up of from 100 million million million different cells.
Some are manufactured continuously.
A 170 billion red cells form daily to carry oxygen.
10 billion white cells form to fight disease.
Others, like the cells of the nose and ear,
renew themselves so vigorously, they just keep on growing all life long.
But eventually, something goes wrong.
[they began to die.]


Human Growth Harmon
"Whilst we're going through childhood and adolescence,
our bodies are churning out large amounts of growth harmone.
It helps build muscle and repair tissues.
At about the age of 25, levels peak,
then start to drop off."



PLANET OF RED SKY to Blue Sky.
"Four billion years ago, when life started on this planet,
the world looked very different,
volcanoes were active, belching in to the atmosphere,
a mixture of corbon dioxide and sulphur.
These gases would have coloured the sky red.

Blue Green Algae dominated the planet.
They used the energy from the sun,
and combined it with the gases in the atmosphere to make food.
But, as they spread over the planet,
these algae produced this new gas:
oxygen.
Levels in the atmosphere slowly rose from almost nothing to over 20%,
and turned the sky blue."


MITOCHONDRIA

"oxygen is a highly explosive reactive gas."
... oxygen is dangerous.
2.5 billion years ago, oxygen would have killed most of the life forms
it came in contact with.

But one microbe found its way to harnesssing the explosive power of this gas.
It's called a mitochondrion.
Each mitochondrion became a miniature power station."


"Every living creature on this planet has mitochondra within there cells.
They are the power plants that fuel all life, including us.

They're like millions of tiny batteries"


"(mitochondria are) in the tails of sperm"
and so the same story with egg, ... under the laster they glow, like the sun."


"Our every movement is powered by them.
Our every breath brings them the oxygen they need.

But there's a heavy cost.
With every breath we age.

Life-giving oxgen is slowly killing us"



"oxygen isn't just explosive it's corrosive.
when oxygen touched pure iron it starts a chemical reaction that turns it to rust."
(so it rusts your body as well)


"The brain is about 2% of the weight of the human body,
but consumes about 20% of the oxygen.
..
the brain cell are particularly susceptible to the toxic effects of oxygen."



[eating less, eating more vegetables, slower heart beat ... may increase your life. because in this you you create less 'fee-radicals and more antioxidants. But in long run it can weaken your bones (so keep eating meat time by time)]



"Steve Austed believes birds are able to resist oxygen attack because they have much better defenses.
Their cells are packed with powerful antioxidants.
If he's right, then it's antioxidants
that are likely to form the basis of any elixir of youth."


[Drugs can extend the lifespan. Experiments are successful at the level of Nematodes...]


"The new science of genetics promises to change our world beyond all recognition.
Whether it's for better or for worse will not be decided by science, but by society."

________________________