sciencetimewithalbertrex

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The Cosmic Calendar

This timeline beautifully extends the Cosmic Calendar concept, aligning key cosmological and evolutionary events to dates in a calendar year to illustrate their relative timing in the history of the universe.

Cosmology Timeline

1 Jan (13.8 Gya): Big Bang. The universe begins its expansion, and cosmic background radiation is emitted.

19 Jan (13.1 Gya): The oldest known Gamma Ray Burst occurs.

26 Jan (12.85 Gya): The first galaxies begin to form.

16 Mar (11 Gya): Formation of the Milky Way Galaxy.

13 May (8.8 Gya): The Milky Way Galaxy's disk forms.

2 Sep (4.57 Gya): The Solar System forms.

6 Sep (4.4 Gya): Oldest rocks known on Earth.

Evolution of Life on Earth Timeline

14 Sep (4.1 Gya): First known remains of biotic life.

21 Sep (3.8 Gya): Life begins with Prokaryotes (single-celled organisms without a nucleus).

30 Sep (3.4 Gya): Photosynthesis begins, producing oxygen as a byproduct.

29 Oct (2.4 Gya): Oxygenation of Earth's atmosphere begins.

9 Nov (2 Gya): First complex cells (Eukaryotes) evolve.

5 Dec (0.8 Gya): First multicellular life forms.

7 Dec (0.67 Gya): Simple animals appear.

14 Dec (0.55 Gya): Arthropods (ancestors of insects and arachnids) evolve.

17 Dec (0.5 Gya): Fish and proto-amphibians emerge.

20 Dec (0.45 Gya): Land plants evolve, and the Ordovician–Silurian extinction events take place.

21 Dec (0.4 Gya): Insects and seeds appear.

22 Dec (0.36 Gya): Amphibians evolve; the Late Devonian extinction occurs.

23 Dec (0.3 Gya): Reptiles emerge.

24 Dec (0.25 Gya): The Permian–Triassic extinction event wipes out a majority of life.

25 Dec (0.23 Gya): Dinosaurs dominate the Earth.

26 Dec (0.2 Gya): Mammals evolve; the Triassic–Jurassic extinction event occurs.

27 Dec (0.15 Gya): Birds (avian dinosaurs) appear.

28 Dec (0.13 Gya): Flowers evolve.

30 Dec, 06:24 (0.065 Gya): The Cretaceous–Paleogene extinction event occurs, wiping out non-avian dinosaurs.

Human Evolution Timeline

30 Dec (65 Mya): Primates evolve.

31 Dec, 06:05 (15 Mya): Apes evolve.

31 Dec, 14:24 (12.3 Mya): Hominids (human ancestors) emerge.

31 Dec, 22:24 (2.5 Mya): Primitive humans and stone tools appear.

31 Dec, 23:44 (0.4 Mya): Humans domesticate fire.

31 Dec, 23:52 (0.2 Mya): Anatomically modern humans evolve.

31 Dec, 23:55 (0.11 Mya): The most recent glacial period begins.

31 Dec, 23:58 (0.035 Mya): Humans create sculpture and painting.

31 Dec, 23:59:32 (0.012 Mya): Agriculture begins.

Human History Timeline

31 Dec, 23:59:33 (12,000 years ago): The last Ice Age ends.

31 Dec, 23:59:41 (8,300 years ago): Doggerland floods.

31 Dec, 23:59:46 (6,000 years ago): The Chalcolithic (Copper Age) begins.

31 Dec, 23:59:47 (5,500 years ago): Early Bronze Age; Stonehenge Cursus is built.

31 Dec, 23:59:48 (5,000 years ago): The First Dynasty of Egypt and the Early Dynastic period in Sumer begin; Indus Valley civilization starts.

31 Dec, 23:59:49 (4,500 years ago): The alphabet and the Akkadian Empire emerge; the wheel is invented.

31 Dec, 23:59:51 (4,000 years ago): The Code of Hammurabi is written; Middle Kingdom of Egypt.

31 Dec, 23:59:52 (3,500 years ago): Late Bronze Age to early Iron Age; Minoan eruption.

31 Dec, 23:59:53 (3,000 years ago): The Iron Age begins; classical antiquity develops.

31 Dec, 23:59:54 (2,500 years ago): The era of Buddha, Mahavira, Zoroaster, Confucius, Classical Greece, and the Roman Republic.

31 Dec, 23:59:55 (2,000 years ago): The Roman Empire, Ptolemaic astronomy, Christ, and invention of numeral 0.

31 Dec, 23:59:56 (1,500 years ago): Muhammad, the rise of the Byzantine Empire, and the Maya civilization.

31 Dec, 23:59:58 (1,000 years ago): The Mongol Empire, Renaissance, and voyages of Columbus.

31 Dec, 23:59:59 (500 years ago): The modern era, including events from the Scientific Revolution to the Digital Age.

This detailed timeline helps us grasp how short human history is in comparison to the age of the universe. In the "final second" of the Cosmic Calendar, entire human civilization—from the earliest tools to modern times—unfolds, showing how recent our existence is in cosmic terms.

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Time Travel: Is It Possible in the Past or Future?

Introduction

The idea of time travel has always fascinated scientists, philosophers, and even storytellers. But is it really possible to travel through time, either into the past or the future? Stephen Hawking, in his famous book The Universe in a Nutshell, explores this idea in depth using both physics and mathematics. In this research article, we will break down the concept of time travel in simple terms and explore the scientific theories, hypotheses, experiments, and fun facts surrounding this mind-boggling topic.

Time Travel in Physics

Time, as described in physics, is not just a straight line that we follow but is part of a "space-time" fabric. Albert Einstein’s Theory of Relativity revolutionized how we think about time and space. According to his General Theory of Relativity, time and space are interconnected, forming a four-dimensional fabric called "spacetime."

Time Dilation: One key aspect of time travel is "time dilation," which is a proven phenomenon. It means that time moves slower for objects moving at extremely high speeds (close to the speed of light). This has been observed in experiments involving particles in accelerators and in atomic clocks flown on airplanes. If you could travel close to the speed of light, time would pass slower for you than for someone on Earth. In theory, this means you could travel into the future.

Time Travel to the Future

Stephen Hawking and many other scientists believe that traveling to the future is theoretically possible. Based on Einstein's Theory of Relativity:

Special Relativity: As we approach the speed of light, time slows down for the traveler relative to someone who remains stationary. If astronauts travel in a spaceship at nearly the speed of light and return to Earth, they would find that more time has passed on Earth than for them. This is one way to "travel into the future."

Gravitational Time Dilation: In the presence of a strong gravitational field (like near a black hole), time also passes slower. This is another way that future time travel could occur.Mathematical Expression:Δt′=Δt1−v2c2\Delta t' = \Delta t \sqrt{1 - \frac{v^2}{c^2}}Δt′=Δt1−c2v2​​Where:

Δt′\Delta t'Δt′ is the time experienced by the traveler.

Δt\Delta tΔt is the time experienced by a stationary observer.

vvv is the velocity of the moving object.

ccc is the speed of light.

Time Travel to the Past

Traveling to the past, however, is much more complicated and controversial. According to the laws of physics as we currently understand them, there is no clear way to travel to the past without causing problems like "paradoxes."

The Grandfather Paradox: This paradox is one of the biggest problems with time travel to the past. It asks, "What happens if you travel back in time and prevent your grandfather from meeting your grandmother?" If you do that, you would never be born, but if you were never born, how could you go back in time to prevent their meeting?

Wormholes: In The Universe in a Nutshell, Hawking discusses the idea of "wormholes" as a possible method of time travel. A wormhole is like a tunnel that connects two distant points in spacetime. In theory, if one end of the wormhole moves differently through time than the other, it could create a passage between two different times. However, keeping a wormhole stable enough for time travel would require "exotic matter" (with negative energy), which we don’t yet fully understand.Mathematical Expression (Wormholes and Einstein-Rosen Bridge):ds2=−c2dt2+(dr21−2GMr)+r2(dθ2+sin⁡2θdϕ2)ds^2 = -c^2 dt^2 + \left( \frac{dr^2}{1-\frac{2GM}{r}} \right) + r^2 (d\theta^2 + \sin^2\theta d\phi^2)ds2=−c2dt2+(1−r2GM​dr2​)+r2(dθ2+sin2θdϕ2)This is the Schwarzschild metric that describes a non-rotating black hole or a wormhole.

Cosmic Strings: Another interesting idea for time travel is "cosmic strings." These are thin, high-energy tubes left over from the early universe. Two cosmic strings moving past each other at high speeds could bend spacetime enough to allow for time travel.

Hypotheses of Time Travel

Closed Timelike Curves (CTCs): This hypothesis suggests that under certain conditions, spacetime could bend in such a way that an object could return to its own past. These are called "closed timelike curves." The concept was explored in theoretical physics but has many limitations and is highly speculative.

Hawking's Chronology Protection Conjecture: Stephen Hawking proposed a hypothesis called the Chronology Protection Conjecture, which says that the laws of physics prevent time travel to the past. According to Hawking, if time travel to the past were possible, it would create paradoxes and instability in the universe. He believed that nature has a way of "protecting" the timeline from such disruptions.

Experiments and Evidence

While time travel to the past has not been observed, there are real experiments that suggest time travel to the future is possible in small ways:

Twin Paradox: In this thought experiment, one twin travels at high speed into space while the other stays on Earth. When the traveling twin returns, they are younger than their sibling due to time dilation. This is not just a theory; a similar effect has been observed in experiments with particles in particle accelerators.

Muon Experiments: Muons are particles that decay very quickly. When scientists send muons at close to the speed of light, they last longer than they would at rest, due to time dilation. This is a form of time travel into the future for these particles.

Fun Facts about Time Travel

Time Travel in Pop Culture: The concept of time travel is popular in movies like Back to the Future and Interstellar, where the characters explore the idea of moving through time. While these movies are entertaining, they are often based on real scientific ideas.

Faster-than-light Travel: If it were possible to travel faster than light, you could theoretically arrive at a destination before you left, which could be a form of time travel. However, according to Einstein’s Theory of Relativity, nothing can travel faster than the speed of light.

Conclusion

Time travel, especially to the future, is not just science fiction but is rooted in the laws of physics, thanks to Einstein’s Theory of Relativity. However, traveling to the past remains a challenging and speculative concept, with paradoxes like the Grandfather Paradox making it difficult to imagine without breaking the laws of nature. While we don't yet have the technology or understanding to make time travel possible, the idea continues to fascinate scientists and the public alike. From wormholes to cosmic strings, the possibilities for time travel keep us curious and engaged in the mysteries of the universe.

References

Hawking, Stephen. The Universe in a Nutshell. Bantam Books, 2001.

Einstein, Albert. Relativity: The Special and General Theory. Crown Publishing, 1916.

Thorne, Kip S. Black Holes & Time Warps: Einstein's Outrageous Legacy. W.W. Norton & Company, 1994.

Carroll, Sean. Spacetime and Geometry: An Introduction to General Relativity. Addison-Wesley, 2003.

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Why Does Thunder follow Lighting?

During the rainy season we often see lightning in the sky followed by thunder. Do you know what this lightning is and how thunder follows it? In ancient times whenever man saw lightning in the sky and heard thunder he used to believe that gods were angry and punishing him for some sin. Benjamin Franklin was the first person who, in 1872, scientifically explained the occurrence of lightning. In fact, whenever the sky gets overcast with clouds, the small particles of water present in them get charged due to air friction. 

In the process, some clouds become positively charged, while some others negatively charged. When a positively-charged cloud approaches a negatively charged one. There develops a potential difference of millions of volts between them. Because of this high voltage, there is a sudden electric discharge through the air between the two clouds and a streak of light is seen. This is called 'lightning'. The electric discharge through the air produces a large amount of heat due to which the atmospheric air suddenly expands.

With this sudden expansion, the innumerable molecules of the air collide with one another producing sound. This is called 'thunder'. Although lightning and thunder are produced simultaneously, yet we see the flash of lightning first. It is so because the velocity of light is very high i.e.,300000 kms.per second. On the other hand velocity of sound is only 332 metres per second. Thus, because of its high velocity, light immediately reaches our eyes, but the sound takes some time to reach our ears.

Whenever a charged cloud passes by some tall tree or high building, by induction, it produces the opposite charge on that tree or building. When the amount of charge so produced is very high, there is a sudden electric discharge in the air. It is then said that lightning has struck such tree or building.

To protect high buildings from such mishaps pointed rods of copper or some other metal are fixed on the top of buildings which passes through them and are buried deep in the earth.

These are called 'lightning conductors'. Whenever some charged cloud passes by such a building and produces opposite charge on it, the charge goes to the earth through the rod and does not damage the building. This is how buildings are protected from the lightning. 

"THERE IS A CRACK IN EVERYTHING, THAT'S HOW THE LIGHT GETS IN."