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  1. science.nasa.gov › universe › overviewOverview - NASA Science

    The origin, evolution, and nature of the universe have fascinated and confounded humankind for centuries. New ideas and major discoveries made during the 20th century transformed cosmology – the term for the way we conceptualize and study the universe – although much remains unknown.

    • Universe

      The Wilkinson Microwave Anisotropy Probe (WMAP) satellite...

    • The Emergence of Matter in The Universe
    • Quantum Fluctuations and The Fabric of Spacetime
    • Theoretical Physics and The Cosmos
    • Cycles from Almost Nothing
    • Penrose’s Theory of Conformal Cyclic Cosmology
    • Philosophical Implications and Future Discoveries
    • Penrose’s Cyclical Universe: A Myth Reborn

    But before we get to that, let’s take a look at how “material” – physical matter – first came about. If we are aiming to explain the origins of stable matter made of atoms or molecules, there was certainly none of that around at the Big Bang– nor for hundreds of thousands of years afterwards. We do in fact have a pretty detailed understanding of ho...

    But how did these particles come to exist in the first place? Quantum field theory tells us that even a vacuum, supposedly corresponding to empty spacetime, is full of physical activity in the form of energy fluctuations. These fluctuations can give rise to particles popping out, only to be disappear shortly after. This may sound like a mathematica...

    We still don’t have a perfect theory of quantum gravity, but there are attempts – like string theory and loop quantum gravity. In these attempts, ordinary space and time are typically seen as emergent, like the waves on the surface of a deep ocean. What we experience as space and time are the product of quantum processes operating at a deeper, micr...

    To truly answer the question of how something could arise from nothing, we would need to explain the quantum state of the entire universe at the beginning of the Planck epoch. All attempts to do this remain highly speculative. Some of them appeal to supernatural forces like a designer. But other candidate explanations remain within the realm of phy...

    Conformal cyclic cosmology offers some detailed, albeit speculative, answers to the question of where our Big Bang came from. But even if Penrose’s vision is vindicated by the future progress of cosmology, we might think that we still wouldn’t have answered a deeper philosophical question – a question about where physical reality itself came from. ...

    Penrose and his collaborators believe they may have spotted these traces already, attributing patterns in the Planck data to radiation from supermassive black holes in the previous universe. However, their claimed observations have been challenged by other physicistsand the jury remains out. Endless new cycles are key to Penrose’s own vision. But t...

    For a philosopher of science, Penrose’s vision is fascinating. It opens up new possibilities for explaining the Big Bang, taking our explanations beyond ordinary cause and effect. It is therefore a great test case for exploring the different ways physics can explain our world. It deserves more attention from philosophers. For a lover of myth, Penro...

    • How it all started. The Big Bang was not an explosion in space, as the theory's name might suggest. Instead, it was the appearance of space everywhere in the universe, researchers have said.
    • The universe's first growth spurt. When the universe was very young — something like a hundredth of a billionth of a trillionth of a trillionth of a second (whew!)
    • Too hot to shine. Light chemical elements were created within the first three minutes of the universe's formation. As the universe expanded, temperatures cooled and protons and neutrons collided to make deuterium, which is an isotope of hydrogen.
    • Let there be light. About 380,000 years after the Big Bang, matter cooled enough for electrons to combine with nuclei to form neutral atoms. This phase is known as "recombination," and the absorption of free electrons caused the universe to become transparent.
  2. The expansion of the universe is the increase in distance between gravitationally unbound parts of the observable universe with time. [1] It is an intrinsic expansion, so it does not mean that the universe expands "into" anything or that space exists "outside" it.

  3. Oct 31, 2024 · Over the last century or so, science has homed in on an answer: the Big Bang. This describes how the Universe was born in a cataclysmic explosion almost 14 billion years ago. In a tiny fraction of a second, the observable universe grew by the equivalent of a bacterium expanding to the size of the Milky Way.

  4. The Wilkinson Microwave Anisotropy Probe (WMAP) satellite returned data that allowed astronomers to precisely assess the age of the universe to be 13.77 billion years old and to determine that atoms make up only 4.6 percent of the universe, with the remainder being dark matter and dark energy.

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  6. The universe contains all the energy and matter there is. Much of the observable matter in the universe takes the form of individual atoms of hydrogen, which is the simplest atomic element, made of only a proton and an electron (if the atom also contains a neutron, it is instead called deuterium).

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