Science-oasis

Vous n'êtes pas connecté. Connectez-vous ou enregistrez-vous

Science

Voir le sujet précédent Voir le sujet suivant Aller en bas  Message [Page 1 sur 1]

1 Science le Dim 8 Aoû - 15:15

The king

avatar
Super Admin
Super Admin
Through The Wormhole: Beyond The Darkness

What is the universe made of? If you answered stars, planets, gas and dust, you’d be dead wrong. Thirty years ago, scientists first realized that some unknown dark substance was affecting the way galaxies moved.

Today, they think there must be five times as much dark matter as regular matter out there. But they have no idea what it is — only that it’s not made of atoms, or any other matter we are familiar with. And Dark Matter is not the only strange substance in the Universe — a newly discovered force, called Dark Energy, seems to be pushing the very fabric of the cosmos apart.

The composition of the universe may seem straightforward, something you mastered back in your junior high science class — galaxies made up of planets and stars, stars made up of burning gases and dust. But this idea of the universe only includes the parts that we can see, either with the naked eye or even with powerful telescopes.

According to scientists, the visible portions of the universe account for less than 95 percent of what is actually out there in the great expanse of space. Much of the universe is made up of something we can’t see. We call this something “dark matter,” and we only discovered its existence because something else was missing.


_________________

www.science-oasis.onlc.fr
Voir le profil de l'utilisateur http://www.science-oasis.onlc.fr

2 Re: Science le Dim 8 Aoû - 15:16

The king

avatar
Super Admin
Super Admin
Through The Wormhole: What Are We Made Of?

Our understanding of the universe and the nature of reality itself has drastically changed over the last 100 years, and it’s on the verge of another seismic shift. In a 17-mile-long tunnel buried 570 feet beneath the Franco-Swiss border, the world’s largest and most powerful atom smasher, the Large Hadron Collider, is powering up.

Its goal is nothing less than recreating the first instants of creation, when the universe was unimaginably hot and long-extinct forms of matter sizzled and cooled into stars, planets, and ultimately, us. These incredibly small and exotic particles hold the keys to the greatest mysteries of the universe. What we find could validate our long-held theories about how the world works and what we are made of. Or, all of our notions about the essence of what is real will fall apart.

What are we made of? The question has rankled scientists and philosophers for millennia, and even with the amazing progress made in fields like particle physics and astronomy, we are left with only a partial answer. We know, of course, that the visible world is composed of protons, neutrons and electrons that combine to form atoms of different elements, and we know those elements are the building blocks of the planets and stars that give rise to solar systems and galaxies.

What we didn’t know until very recently, however, is that those protons, neutrons and electrons appear to form less than 5 percent of the universe, and questions remain about how these building blocks arose. If regular matter represents only a small slice of the universe, what is the rest of the universe made of?

Such questions prompted the construction of the Large Hadron Collider (LHC) beneath the border between France and Switzerland. As the world’s largest particle accelerator, experts designed the LHC to recreate conditions that occurred shortly after the very foundation of universe itself. Here are a few of the mysteries scientists hope the LHC and other particle accelerators can shed light on.


_________________

www.science-oasis.onlc.fr
Voir le profil de l'utilisateur http://www.science-oasis.onlc.fr

3 Re: Science le Dim 8 Aoû - 15:19

The king

avatar
Super Admin
Super Admin
Darwin’s Secret Notebooks

Using Darwin’s own diary and field notes as a travel guide, retrace Darwin’s expedition beyond the Galapagos to uncover the forgotten evidence that inspired his revolutionary work.

He wasn’t a mathematician. He wasn’t an inventor. He was just a 20-something guy who liked to poke around in the dirt.

Yet, Charles Darwin developed a theory of evolution so significant that it forms the bedrock of biology, and so radical it is still controversial in some circles today.

In 1859, when he was 50, Darwin published “On the Origin of Species,” the work that outlined the theory of natural selection and left every high-schooler hankering for a trip to the Galapagos Islands.

He was only 22 when he began the five-year adventure that led him to his legacy. Charles Darwin’s five-year expedition led him to his theory of evolution. Feb. 12, 2009 marked his 200th birthday.




_________________

www.science-oasis.onlc.fr
Voir le profil de l'utilisateur http://www.science-oasis.onlc.fr

4 Re: Science le Dim 8 Aoû - 15:20

The king

avatar
Super Admin
Super Admin
Through The Wormhole: Are We Alone?

Aliens almost certainly do exist. So why haven’t we yet met E.T.? It turns out we’re only just developing instruments powerful enough to scan for them, and science sophisticated enough to know where to look. As a result, race is on to find the first intelligent aliens.

But what would they look like, and how would they interact with us if we met? The answers may come to us sooner than we imagine, for one leading astronomer believes she may already have heard a hint of their first efforts to communicate.

Of all the signals received in the search for intelligent extraterrestrials, the Wow! signal is one that many people remember. And Jerry Ehman was the man who wrote it. Ehman taught astronomy and electrical engineering at Ohio State University and worked on early projects for Big Ear, a radio telescope at the university.

These telescopes collect radio waves from space. Because cosmic radio waves are weak, the telescope collecting dishes have to be large, more than three football fields long in Big Ear’s case.

Ohio State let Ehman go after cutting Big Ear’s funding. Undeterred, he came back to Big Ear as a volunteer. Two colleagues helped Ehman. Without John Kraus, who conceived of the telescope, Big Ear wouldn’t have been listening.

Robert Dixon, Kraus’s former student, designed Big Ear’s search plan, choosing the radio wavelength to listen to, and he corrected the listening to account for our galaxy’s spin. Without Dixon’s correction, Big Ear would have listened to the wrong wavelength.


_________________

www.science-oasis.onlc.fr
Voir le profil de l'utilisateur http://www.science-oasis.onlc.fr

5 Re: Science le Dim 8 Aoû - 15:21

The king

avatar
Super Admin
Super Admin
Extreme Universe

Ever wondered what would happen if you were sucked into a black hole? Or, if wormholes could make time travel a reality?

And could life on Earth survive a huge meteor strike like the one that took out the dinosaurs?

Now you can find out in this captivating series. Join experts as they unravel the most mind-boggling mysteries of the cosmos, using the latest scientific theories, dramatic time sequences and everyday examples of incredible forces.

1. Is Anyone Out There? Exploring our own planet for clues as to what extraterrestrial life might look like, find out how scientists are searching for aliens and what might happen if we were ever to make contact.

2. Collision Course. Meet the scientists working to defend us from a cataclysmic crash, before we explore deep space collisions on a colossal scale.

3. Space Storms. Witness the relentless power of Earth’s worst weather, before travelling the universe to find the 17,500kmh winds and methane storms of space.

4. Edge Of Space. Delve into the unknown on a journey into deep oceans and deep space, as we seek the answers to some of mankind’s most unfathomable questions.

5. Time Bombs. Planets, moons and stars can all face violent upheaval at any moment. Is it possible to predict when Mother Nature will strike?

6. Star Gates. Throughout history, humans have been fascinated by the stars. Discover how astronomy played a crucial role in early civilisations.


_________________

www.science-oasis.onlc.fr
Voir le profil de l'utilisateur http://www.science-oasis.onlc.fr

6 Re: Science le Dim 8 Aoû - 15:22

The king

avatar
Super Admin
Super Admin
Through The Wormhole: What Happened Before the Beginning?

Every cosmologist and astronomer agrees: our Universe is 13.7 billion years old. Using cutting-edge technology, scientists are now able to take a snapshot of the Universe a mere heartbeat after its birth.

Armed with hypersensitive satellites, astronomers look back in time to the very moment of creation, when all the matter in the Universe exploded into existence. It is here that we uncover an unsolved mystery as old as time itself – if the Universe was born, where did it come from? Meet the leading scientists who have now discovered what they believe to be the origin of our Universe, and a window into the time before time.

The big bang theory holds that the entire universe was once packed tightly into an unimaginably dense and tiny space, known as a “singularity.” That is, until roughly 13.7 billion years ago, when a colossal burst of energy and pressure started to give rise to entire worlds, galaxies and interstellar particles, forming the universe as we know it today.

But what brought about that big bang? Physicists are left scratching their heads at that question. Since the universe began on such a tiny level, the laws of relativity don’t fully apply. Instead, quantum theory, which deals with the lawless and bizarre world of the very small, must also be summoned.

Successfully answering the question of what existed before the big bang would require bridging the gap between the so-far mutually incompatible worlds of relativism and quantum mechanics. But even though that bridge has yet to be constructed, theories abound.

“Our universe could have either popped into existence or collided with another universe,” theoretical physicist Michio Kaku told scienceline.org. “Big Bangs happen all the time.”


_________________

www.science-oasis.onlc.fr
Voir le profil de l'utilisateur http://www.science-oasis.onlc.fr

7 Re: Science le Dim 8 Aoû - 15:23

The king

avatar
Super Admin
Super Admin
Through The Wormhole – Is Time Travel Possible?

Einstein’s Theory of Relativity says that time travel is perfectly possible — if you’re going forward. Finding a way to travel backwards requires breaking the speed of light, which so far seems impossible. But now, strange-but-true phenomena such as quantum nonlocality, where particles instantly teleport across vast distances, may give us a way to make the dream of traveling back and forth through time a reality. Step into a time machine and rewrite history, bring loved ones back to life, control our destinies.

But if we succeed, what are the consequences of such freedom? Will we get trapped in a plethora of paradoxes and multiple universes that will destroy the fabric of the universe? Einstein said that nothing travels faster than the speed of light, but when physicists look at how entangled particles behave, they get stuck in a mirage in which that tenet appears not to be true.

Physicists don’t fully understand entanglement, beyond it being a relationship between particles. If you want to know what entanglement looks like, pull up a chair to an experiment that has produced it. Researchers at the University of Nice-Sophia Antipolis and the University of Geneva shone a laser made of photons, the basic units of light, into the crystal. When the laser’s photons hit irregularities in the crystal, single photons sometimes split into two. These daughter photons were related to one another, and to their parent photon, in how much energy they had.

You can think of the parent photon as being like a train, and the crystal like many bumps. When the train hit the bumps, it broke into two chains of cars with related directions and speeds. These daughter photons weren’t just related, but entangled. Particles are entangled if they’re related in one property but random in the rest.


_________________

www.science-oasis.onlc.fr
Voir le profil de l'utilisateur http://www.science-oasis.onlc.fr

8 Re: Science le Dim 8 Aoû - 15:24

The king

avatar
Super Admin
Super Admin
Ice Age Columbus: Who Were the First Americans?

Traditional history tells us that European settlers discovered America about the time of the Renaissance. But revolutionary new archaeological data and the latest DNA research reveal that Europeans visited our shores far earlier – some 17,000 years before Columbus was even born.

Filmed in glorious high definition, this two-hour, epic drama follows an intrepid family of stone age hunters as they trek from their homeland in southwestern France, cross 3,000 miles of ocean and eventually make their first permanent settlement in what is today the northeastern U.S.

Along the way, they overcome starvation and storms with the help of a revolutionary weapons technology they would later bequeath to the native peoples of the Americas.

But awaiting the pioneers’ arrival is a stark, empty continent, filled with a plethora of bizarre and lethal animals – all brought to life by brilliant computer animation. Firmly rooted in the latest scientific discoveries, it’s a compelling vision of the greatest migration in human history.


_________________

www.science-oasis.onlc.fr
Voir le profil de l'utilisateur http://www.science-oasis.onlc.fr

9 Re: Science le Dim 8 Aoû - 15:24

The king

avatar
Super Admin
Super Admin
Through the Wormhole – The Riddle of Black Holes

They are the most powerful objects in the universe. Nothing, not even light, can escape the gravitational pull of a black hole. Astronomers now believe there are billions of them out in the cosmos, swallowing up planets, even entire stars in violent feeding frenzies. New theoretical research into the twisted reality of black holes suggests that three-dimensional space could be an illusion. That reality actually takes place on a two-dimensional hologram at the edge of the universe.

Black holes are almost as difficult to imagine as they are to detect, but a few scientists have been up for the task over the centuries. Cambridge scholar John Michell wrote a paper in 1783 in which he hypothesized the existence of “dark stars” — stars so large and with so much gravity that light wouldn’t escape their surfaces. Most astronomers of the day thought it was an absurd notion.

Then, in 1915, Einstein published his general theory of relativity, providing a framework that allowed for a reinterpretation of Michell’s hypothesis. An Indian graduate student by the name of Subrahmanyan Chandrasekhar piggybacked on Einstein’s theories to suggest that stars of a certain size — much larger than our sun — would experience a catastrophic collapse at the end of their lives, thereby transforming the bodies into cosmic vacuum cleaners whose powerful gravity could suck all light and matter into their black maws.


_________________

www.science-oasis.onlc.fr
Voir le profil de l'utilisateur http://www.science-oasis.onlc.fr

10 Re: Science le Dim 8 Aoû - 15:25

The king

avatar
Super Admin
Super Admin
The Human Family Tree


On a single day on a single street, with the DNA of just a couple of hundred random people, National Geographic Channel sets out to trace the ancestral footsteps of all humanity.

Narrated by Kevin Bacon, The Human Family Tree travels to one of the most diverse corners of the world — Queens, N.Y. — to demonstrate how we all share common ancestors who embarked on very different journeys.

Regardless of race, nationality or religion, all of us can trace our ancient origin back to the cradle of humanity, East Africa. What did our collective journey look like, and where did it take your specific ancestors?

At what point in our past did we first cross paths with the supposed strangers living in our neighborhood? Now, in The Human Family Tree, the people of this quintessential American melting pot find out that their connections go much deeper than a common ZIP code.



_________________

www.science-oasis.onlc.fr
Voir le profil de l'utilisateur http://www.science-oasis.onlc.fr

11 Re: Science le Dim 8 Aoû - 15:29

The king

avatar
Super Admin
Super Admin
From Big Bang to Us – Made Easy

This series explains the scientific evidence for our origins, from the Big Bang to the human migration out of Africa, in a way that most 7th-graders would understand.

It challenges people who believe we were created by a deity 6,000 years ago to confront the evidence instead of ignoring it.

About the Author: Potholer. I’ve been a journalist for 20 years, 14 years as a science correspondent. My degree is in geology, but while working for a science magazine and several science programs I had to tackle a number of different fields, from quantum physics to microbiology.

My particular talent was my ignorance. By not understanding half of what I was assigned to cover, I had to reduce scientific discoveries from the complex to the simple.

If I wrote it in a way that I could understand it, then my readers could understand it.


_________________

www.science-oasis.onlc.fr
Voir le profil de l'utilisateur http://www.science-oasis.onlc.fr

12 Re: Science le Dim 8 Aoû - 15:30

The king

avatar
Super Admin
Super Admin
Evolution Primer

Isn’t evolution just a theory? Learn the difference between the scientific and everyday use of key vocabulary words.

Who was Charles Darwin? Discover how Darwin’s curiosity, his passion for natural history, his voyage on the Beagle, and his use of the scientific process led to the publication of his groundbreaking book.

How do we know evolution happens? See how different lines of evidence contribute to our picture of evolution. Learn about the fossil evidence for whales’ land-dwelling ancestors.

How does evolution really work? Travel to Ecuador to see how the process of natural selection operates in populations of rain-forest hummingbirds.

Did humans evolve? Examine the fossil and molecular evidence that supports the evolution of humans from earlier primate ancestors.

Why does evolution matter now? Learn how tuberculosis is transmitted and why the evolution of multi-drug resistant strains of TB in Russia affects us all.

Why is evolution controversial anyway? Consider different points of view, as scientists, religious leaders, and college students share their opinions about evolution, science, and religious faith.


_________________

www.science-oasis.onlc.fr
Voir le profil de l'utilisateur http://www.science-oasis.onlc.fr

13 Re: Science le Dim 8 Aoû - 15:30

The king

avatar
Super Admin
Super Admin
Can We Make a Star on Earth?

Professor Brian Cox takes a global journey in search of the energy source of the future.

Called nuclear fusion, it is the process that fuels the sun and every other star in the universe.

Yet despite over five decades of effort, scientists have been unable to get even a single watt of fusion electricity onto the grid.

Brian returns to Horizon to find out why. Granted extraordinary access to the biggest and most ambitious fusion experiments on the planet, Brian travels to the USA to see a high security fusion bomb testing facility in action and is given a tour of the world’s most powerful laser.

In South Korea, he clambers inside the reaction chamber of K-Star, the world’s first super-cooled, super-conducting fusion reactor where the fate of future fusion research will be decided.

Nuclear fusion is nature’s power source. From the Sun to the most distant stars, the energy that lights up the Universe is released by sticking hydrogen nuclei together to make helium.

Since hydrogen is the most abundant element in the Universe, it seems sensible to ask whether we might endeavor to do the same and power ourselves out of our serious energy crisis by building stars on Earth.

The problem of course is that stars are big and hot; the Sun is the size of a million Earths, and burns six hundred million tonnes of hydrogen fuel every second.


_________________

www.science-oasis.onlc.fr
Voir le profil de l'utilisateur http://www.science-oasis.onlc.fr

14 Re: Science le Dim 8 Aoû - 15:34

The king

avatar
Super Admin
Super Admin
100 Greatest Discoveries

Scientists have transformed the way we think and live throughout the centuries.

What are the most important scientific discoveries of all time? In no particular order, we present the top 100 in eight different categories.

Explore the universe, the world around you, the world under a microscopic, the Earth under your feet, the past, what makes you, developments in health, and how stuff works.

Chemistry


Earth Science


Physics


_________________

www.science-oasis.onlc.fr
Voir le profil de l'utilisateur http://www.science-oasis.onlc.fr

15 Re: Science le Dim 8 Aoû - 15:37

The king

avatar
Super Admin
Super Admin
DNA – The Molecule of Life

What is the force at the heart of life? What is the engine that drives it forward? That links all living things from the smallest to the largest, that links families through generations, looks, personality, health, and in sickness?

Scientists have searched for the answer for hundreds of years, until 1953 when two young men ran into a British pub shouting that they’ve discovered the secret of life.

The secret was DNA, a microscopic strand of only four chemicals but capable of such infinite variety that it carries the blueprint and directs the growth of every living thing on earth. The genetic revolution was about to begin. This is a documentary about genetics and ethics.


DNA - 1of5 - The Secret of Life
envoyé par JamesWatson. - Cours, soirées et beaucoup d'autres vidéos de la vie étudiante.


DNA - 2of5 - Playing God
envoyé par JamesWatson. - Cours, soirées et beaucoup d'autres vidéos de la vie étudiante.


DNA - 3of5 - The Human Race
envoyé par JamesWatson. - Découvrez plus de vidéos de la vie étudiante.


DNA - 4of5 - Curing Cancer
envoyé par JamesWatson. - Cours, soirées et beaucoup d'autres vidéos de la vie étudiante.


DNA - 5of5 - Pandoras Box
envoyé par JamesWatson. - Plus de vidéos campus.


_________________

www.science-oasis.onlc.fr
Voir le profil de l'utilisateur http://www.science-oasis.onlc.fr

Contenu sponsorisé


Voir le sujet précédent Voir le sujet suivant Revenir en haut  Message [Page 1 sur 1]

Permission de ce forum:
Vous ne pouvez pas répondre aux sujets dans ce forum