Physics, Pixelated

A glowing atom with orbit rings above a study of old books, with packets of light flying out from a glowing ember

Who Started Quantum Mechanics? Planck, Bohr and...

Quantum theory did not begin with one paper. Planck quantized energy in 1900, Bohr quantized the atom in 1913, and Heisenberg’s 1925 matrix mechanics plus the 1927 uncertainty relation made...

Who Started Quantum Mechanics? Planck, Bohr and...

Quantum theory did not begin with one paper. Planck quantized energy in 1900, Bohr quantized the atom in 1913, and Heisenberg’s 1925 matrix mechanics plus the 1927 uncertainty relation made...

Observatory and prism splitting starlight into a spectrum with dark absorption lines

Did Cecilia Payne Discover What Stars Are Made Of?

Cecilia Payne’s 1925 thesis showed that stars differ mainly in temperature, not composition, and that hydrogen and helium vastly outnumber everything else. She then called that result “almost certainly not...

Did Cecilia Payne Discover What Stars Are Made Of?

Cecilia Payne’s 1925 thesis showed that stars differ mainly in temperature, not composition, and that hydrogen and helium vastly outnumber everything else. She then called that result “almost certainly not...

A radio telescope dish on a mountain peak under a sky swirling with the mottled orange and blue glow of ancient light

What Is the Cosmic Microwave Background? The Ol...

Every direction you look, the sky glows faintly in microwaves at 2.725 kelvin. That glow is light released about 380,000 years after the Big Bang. Here is how it formed,...

What Is the Cosmic Microwave Background? The Ol...

Every direction you look, the sky glows faintly in microwaves at 2.725 kelvin. That glow is light released about 380,000 years after the Big Bang. Here is how it formed,...

Red, green and blue quarks bound by crackling flux tubes, one tube snapping in a flash that creates a new quark pair

What Are Gluons, and Why Can’t We See a Single ...

Every proton holds three quarks, yet no experiment has ever pulled a single quark free. The reason is the strange behaviour of gluons, the carriers of the strong force. Here...

What Are Gluons, and Why Can’t We See a Single ...

Every proton holds three quarks, yet no experiment has ever pulled a single quark free. The reason is the strange behaviour of gluons, the carriers of the strong force. Here...

A glowing ladder of energy levels under an aurora, with most of the bright orbs crowded on the top rungs

Can Temperature Be Negative? Negative Absolute ...

Physicists have made systems with negative absolute temperature since 1951. They are not colder than absolute zero; they are hotter than any positive temperature. Here is why, what was measured,...

Can Temperature Be Negative? Negative Absolute ...

Physicists have made systems with negative absolute temperature since 1951. They are not colder than absolute zero; they are hotter than any positive temperature. Here is why, what was measured,...

A cutaway copper pipe with a magnet drifting slowly down inside, wrapped in glowing orange eddy-current loops

Why Does a Magnet Fall Slowly Through a Copper ...

Copper isn’t magnetic, yet a strong magnet dropped down a copper pipe falls in slow motion. The reason is Lenz’s law: the currents the moving magnet induces always push back...

Why Does a Magnet Fall Slowly Through a Copper ...

Copper isn’t magnetic, yet a strong magnet dropped down a copper pipe falls in slow motion. The reason is Lenz’s law: the currents the moving magnet induces always push back...