00:02No one told you the speed of light can be exceeded. How is that possible? It is possible because even
00:08light gets tired and slows down. For example, when it enters water, not only does the water
00:14change its direction, but its speed also slows by a factor of 1.3. In fact, in specially constructed
00:19materials, light slows down even more. In 1999, using a sodium gas cooled close to absolute zero,
00:26researchers slowed light down in that gas to just 60 kilometers per hour. You could have
00:31overtaken it with a car. In 2003, using a similar gas, they slowed light down to 1.5 kilometers per
00:37hour. Now you could have overtaken it even if you were walking. And in 2013, they made light stand
00:43still for a second and a half. So the speed of light can be surpassed, but only if light is
00:48traveling through materials. In a vacuum, it's impossible. It would violate physics. And we don't
00:53want to upset Einstein. Did you know that? Astronomers have photographed the earliest galaxy we've
01:01ever seen. This is it. Meet Jadis. A galaxy over 1,600 light years in diameter and made up
01:08of very young stars. The strangest part? The galaxy formed less than 300 million years after
01:15the Big Bang and already has several hundred million times the mass of our Sun. How did it
01:20become so massive so quickly? We don't know. This galaxy calls into question our models of
01:26how galaxies form, but it doesn't call the Big Bang into question.
01:31And so, thanks to the powerful infrared eyes of the James Webb Space Telescope, we can see
01:37through cosmic dust to uncover these new mysteries. The presence of heavy elements in the Jadis
01:42galaxy, such as dust and oxygen, suggests that several generations of stars have already lived
01:48and died by 300 million years after the Big Bang. That's the mystery. How can that happen
02:07is possible? From the laboratory. Scientists have recreated conditions similar to those in space
02:12in a vacuum chamber, with substances found in stellar nebulae, such as ammonia, atomic carbon
02:17and carbon monoxide. And they discovered that these ingredients can form precursors of amino
02:24acids, which then combine to create peptides. In space? This process is not easy. Because the dust
02:31in these molecular clouds contains frozen water, the formation of peptides is slowed down but not
02:37stopped. Considering that the universe is billions of years old, there's plenty of time and yet another
02:43example in support of panspermia. Glycine, the simplest amino acid, can form in interstellar clouds
02:50long before stars begin to shine. These molecules could travel on comets and meteorites, bringing the seeds
02:58of life to planets like Earth. Imagine that. The building blocks of life are formed in the frozen
03:04depths of space, then brought to our young planet. This could mean that some of the ingredients for
03:10life on Earth are actually extraterrestrial. Isn't it amazing? We are literally stardust.
03:19Aurora Borealis in Romania. Why are we seeing them now and not in the past? Well, the Sun is approaching
03:24a
03:24maximum in its 11-year activity cycle. In fact, NASA announced a powerful solar flare that happened
03:30three days ago. What we're seeing here could be the result of that. On the other hand, some solar
03:35cycles are more intense, others are not. There's also the camera, which amplifies the colors and spreads
03:40the photos on the internet. Especially this red color, which is caused by the solar wind, particles like
03:45electrons and protons that hit the atmosphere at altitudes over 200 kilometers and excite oxygen atoms in the
03:52rarefied air. When the solar wind penetrates deeper into the atmosphere, you get green and then even
03:57blue light. Kind of like a rainbow. Did you see anything? This is what Hyperion looks like,
04:05one of Saturn's moons. It looks like a gigantic sponge from space. Look at this surface. It's about
04:11200 kilometers across and is covered with strange craters like deep cavities similar to a sponge.
04:17Would you want to be there? What's behind these strange craters? Well, images captured by the
04:23Cassini spacecraft revealed something odd. An unknown reddish material. It's believed that the material is
04:32similar to the one covering another of Saturn's moons, Iapetus, but it would be hard to land on this
04:38Saturnian moon. Why? Because it tumbles chaotically in all directions as it orbits around the planet Saturn.
04:45But why does Hyperion look so strange? Probably because it is a fragment of another much larger
04:51natural satellite of Saturn that was destroyed in a massive impact. What remains is a pile of rubble
04:57with low density and high porosity. Basically, a giant sponge floating in space. Have you ever seen
05:04anything like that? We live in an internet world, but people around the world see the internet differently
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06:01Did you know that all life on Earth might have a common ancestor? Let me introduce you to the
06:07grandmother or grandfather of life, Luca, the last universal common ancestor. Scientists believe that
06:14Luca lived about 4.2 billion years ago, several million years earlier than previously thought,
06:20and only 400 million years after the Earth formed. That means Luca lived right in the middle of Earth's
06:27Hadian Eon, a time when our planet was a chaotic world of fire and lava. Luca would have been an
06:34organism similar to prokaryotes, which means it didn't have a nucleus. Think of it as the ancestor.
06:41Well, you get the idea. The grandmother or grandfather of every living thing today. So how do we know that
06:48Luca existed? Scientists compared the genes of living species and traced them back to this common ancestor.
06:55They discovered that Luca would have had some fascinating features, such as an immune system
07:01to fight against ancient viruses. Yes, even 4.2 billion years ago, life was already in a survival game,
07:09fighting against primordial viruses. And guess what? Luca wasn't alone. Its waste was food for other
07:16microorganisms, creating a recycling ecosystem. We're talking about teamwork. From tiny bacteria to blue whales,
07:24every living creature on Earth shares this incredible lineage. Luca's universal genetic code,
07:32the mechanism of synthesis and protein chirality, as well as the use of ATP as an energy battery,
07:39are found in every cell today. So next time you think about life on Earth, remember this,
07:44we are all possibly connected to this ancient microscopic ancestor. Pretty amazing, isn't it?
07:51What? Have you ever wondered which countries consume the most fossil fuels?
07:57Here's the list from 2023. Have you ever wondered which countries consume the most fossil fuels?
08:04Here's the list from 2023. China and the United States are responsible
08:09for almost half of the world's consumption, with China ranking first with 140 exajoules mostly from coal.
08:16For comparison, Germany uses about 9 exajoules. Where does this difference come from?
08:22On one hand, it's because of the large population. China has a population 17 times bigger than Germany.
08:28In fact, the fossil fuel consumption per capita in China is about the same as in Germany. However,
08:35in the United States, the per capita consumption is twice as high. It should be noted that both in
08:40the United States and in the European Union, fossil fuel consumption has decreased by more than 10%
08:45in the last 20 years. Meanwhile, in China and India, it has doubled, mainly due to economic growth.
08:51As we've seen, per capita consumption in China has reached about the same level as in Germany.
08:56Despite the efforts, today in the world, 81.5% of energy is produced from fossil fuels. The energy
09:04transition is happening but fossil fuels still dominate. What do you think? Thank you for
09:09watching the video until the end and thanks to Surfrag for sponsoring. Don't forget about my link in the
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09:20I am Christian Presura, Physics Explained. You are the audience and I wish you all the best. Goodbye.
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