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400 BCE
First idea about atom
Pre-20th Century Foundations
Ancient Philosophies: Reference early speculations about the fundamental nature of matter by philosophers like Democritus (circa 460–370 BC), who proposed the existence of indivisible units called "atoms". -
Electron
Discovery of the Electron: J.J. Thomson discovered the electron, showcasing the first evidence of subatomic particles, which hinted at the complex inner structure of atoms, challenging the notion of atoms as indivisible units. -
Quantum Theory
The Dawn of Quantum Mechanics and Antimatter
1900-1905 - Quantum Theory Begins: Max Planck and Albert Einstein introduce the quantum concept, fundamentally changing the understanding of energy and matter. -
Plum Pudding Model
Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged "soup." Rutherford's gold foil experiment showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus. -
Atomic Model
Rutherford's model proposed that the negatively charged electrons surround the nucleus of an atom. He also claimed that the electrons surrounding the nucleus revolve around it with very high speed in circular paths. -
Discovery of the Atomic Nucleus
1911: Based on the results of the Gold Foil Experiment, Rutherford proposes a new atomic model in which the atom has a small, dense nucleus at its center, surrounded by orbiting electrons. This model revolutionizes the understanding of atomic structure and leads to the development of the planetary model of the atom. -
Bohr Model Of the Atom
In 1913, Niels Bohr proposed a theory for the hydrogen atom, based on quantum theory that some physical quantities only take discrete values. Electrons move around a nucleus, but only in prescribed orbits, and If electrons jump to a lower-energy orbit, the difference is sent out as radiation. -
Dirac's Theory
1928 - Dirac's Theory: Paul Dirac proposes his equation, predicting the existence of particles with the same mass as electrons but opposite charge and spin, laying the theoretical foundation for antimatter. -
Discovery of Neutron
Chadwick is best known for his discovery of the neutron in 1932. A neutron is a particle with no electric charge that, along with positively charged protons, makes up an atom's nucleus. -
Discovery Of Positron
1932 - Discovery of the Positron: Carl Anderson confirms Dirac's prediction by discovering the positron, the antimatter counterpart of the electron, in cosmic rays, marking the first detection of antimatter. -
Antiprotons and Antineutrons
1950s - Antiprotons and Antineutrons: The discovery of the antiproton (1955) and antineutron (1956) in particle accelerators, further expanding the understanding of antimatter. -
CP Violation
1965 - CP Violation: James Cronin and Val Fitch discover CP violation in the decay of kaons, showing that the laws of physics are not identical for matter and antimatter, which has implications for why the universe is made mostly of matter. -
Antihydrogen
1974 - Antihydrogen: Predictions and indirect evidence of antihydrogen (atoms of antimatter) lead to a deeper understanding of matter-antimatter symmetry.
Modern Explorations and Questions -
Frist Production Of Antihydrogen
1995 - First Production of Antihydrogen: CERN announces the first creation of antihydrogen atoms, allowing for comparisons between hydrogen and antihydrogen, crucial for testing fundamental symmetries in physics. -
Advancements in Nuclear Physics and Particle Accelerators:
The Large Hadron Collider (LHC) at CERN confirms the existence of the Higgs boson, a fundamental particle predicted by the Standard Model of particle physics. The discovery further validates the understanding of particle interactions and the role of fundamental forces, building upon Rutherford's work on atomic structure. -
Nuclear Energy and Fusion Research
The International Thermonuclear Experimental Reactor (ITER) project achieves significant milestones in the construction of the world's largest experimental tokamak nuclear fusion reactor. ITER aims to demonstrate the feasibility of nuclear fusion as a sustainable and clean energy source, building upon principles of nuclear physics elucidated by Rutherford. -
Advancements in Nuclear Medicine
Researchers develop new radiopharmaceuticals and imaging techniques for cancer diagnosis and treatment, leveraging advancements in nuclear medicine. These techniques, such as targeted alpha therapy and theranostics, utilize Rutherford's insights into nuclear decay and radiation interactions for improved medical outcomes. -
Capture of the First Image of a Black Hole
The Event Horizon Telescope Collaboration releases the first-ever "image" of a black hole's event horizon, or shadow, located in the center of the galaxy M87. This milestone confirms predictions of general relativity under extreme gravitational conditions and provides insights into galaxy dynamics. -
Achievement in Quantum Supremacy
October 23, 2019: Google Al Quantum and collaborators announce that their quantum computer, Sycamore, performed a specific task in 200 seconds that would take the world's most powerful supercomputer 10,000 years to complete, -enchmark for quantum supremacy. This represents ↓ a significant step forward in quantum computing -
Exploration of Exotic Nuclear States
Experimental studies at facilities such as the Facility for Rare Isotope Beams (FRIB) in the United States and the Radioactive Isotope Beam Factory (RIBF) in Japan uncover new insights into exotic nuclear states and nuclear astrophysics. These studies probe the limits of nuclear stability and shed light on phenomena such as neutron-rich nuclei, expanding upon Rutherford's investigations into nuclear structure.: