Cosmic Field NotesViral videos (Fact Checked)
A popular video about the Webb telescope makes seven big claims. Here's what it said, and what the actual research found.
The "Big Wheel" giant galaxy
"An exceptionally large galaxy in the early universe, 3 times bigger than others at the time."
Real. Published in Nature Astronomy in March 2025 (Wang, Cantalupo and team). We see it about 2 billion years after the Big Bang. It sits in a crowded region about 10 times denser than average, which probably helped it grow fast. Models gave it less than a 2% chance of existing.
What it really challenges: how fast galaxies grow. Not the Big Bang itself. Source
"Dark energy is changing"
"Scientists have now confirmed dark energy is behaving much more strangely than we thought."
"Confirmed" is too strong. In 2025, DESI (a giant 3D map of the universe) found hints that dark energy is weakening, at about 2.8 to 4.2 sigma depending on which other data is combined with it. Physics needs 5 sigma to call something a discovery. In July 2026 a sharper DESI test leaned back towards "dark energy is constant", and other teams argue the hint may be a measuring issue.
Status: genuinely open, and one of the most exciting questions in physics right now. Source
The Hubble tension
"When scientists study the cosmic microwave background they get one value, but predictions from our standard model give a completely different value."
The video mixes this up. The real tension is between the early universe (baby picture of the cosmos, the CMB, read through the standard model: about 67) and the nearby universe (measured with stars and exploding supernovae: about 73). Webb checked Hubble's star measurements and confirmed them. In April 2026 a big team got 73.50 ± 0.81 using many independent methods.
Status: very real, now 5 to 7 sigma. See "The cosmos" tab to play with it. Source
Timescape: "expansion is an illusion created by time"
"Tested in 2017 and found slightly better than the standard model. Clocks in galaxies tick up to a third slower."
This is a real model from the University of Canterbury, New Zealand. The 2017 test was "slightly better". A bigger December 2024 study (Seifert, Wiltshire and team, 1,535 supernovae) claimed "very strong evidence". The model predicts a Milky Way clock runs about 35% slower than one in a giant void. But it is a minority view, and the authors say telescopes like Euclid and Roman are needed to settle it.
Status: an interesting challenger, not the new consensus. Source
"30,000 galaxies all spinning the same way"
"Webb observed 30,000 galaxies and found most of them are rotating in the same direction."
The published Webb study (Lior Shamir, Kansas State, March 2025) looked at 263 galaxies, not 30,000. About two thirds spun one way. Shamir himself says a likely cause is our own Milky Way's rotation making some galaxies look brighter, so they get counted more. I could not find a Webb study of 30,000 or 20,000 galaxies making this claim.
Status: one small study with a likely everyday explanation. Try the coin flip game in "The cosmos". Source
"Our universe is inside a black hole"
"Some scientists are considering the universe was born inside a rotating black hole."
This is an old, fun idea called black hole cosmology. A few scientists explore it, but there's no evidence for it. The spinning galaxies study mentions it only as one possibility.
"The end of the Big Bang theory"
"Why scientists believe this is the end of the Big Bang theory."
None of these results challenge the Big Bang itself: the universe began hot and dense and has been expanding and cooling for about 13.8 billion years. That is backed by the cosmic microwave background and by the amounts of light elements like hydrogen and helium. What's being questioned are the details: what dark energy is, how fast space expands, and how quickly galaxies grew.
Maths ABC: the building blocks
Every scary looking formula is made from a few simple pieces. Start with the picture story below (made for a 6 year old), then try the blocks underneath.
Squared means "times itself", and it makes a flat area
5 squared, written 5², means 5 × 5 = 25. Why "squared"? Because if you lay 5 rows of 5 tiles, you get a square made of 25 tiles.
Real world: a 12 inch pizza is twice as wide as a 6 inch pizza, but it has 4 times as much pizza, because area grows with the square.
In space: light from a star spreads out over a growing sphere. Twice as far away, the light is spread over 4 times the area, so the star looks 4 times dimmer. That's why so many physics formulas have a ² in them.
Cubed means "times itself, three times", and it makes a box
2 cubed, written 2³, means 2 × 2 × 2 = 8. Stack sugar cubes 2 long, 2 wide and 2 tall and you get 8 cubes.
Real world: make a cardboard box twice as long, twice as wide and twice as tall, and it holds 8 times as many toys.
In space: if the universe gets twice as big in every direction, there is 8 times as much room, so the same matter is spread 8 times thinner. That's the a³ in the Omega Lambda formula.
"To the power" means "how many times you multiply"
2 to the power 5, written 2⁵, means 2 × 2 × 2 × 2 × 2 = 32. The little number tells you how many 2s to multiply. Squared is just "to the power 2" and cubed is "to the power 3".
Real world: fold a sheet of paper in half and it's 2 layers thick. Fold again: 4. Again: 8. Each fold is one more power of 2, which is why you can't fold paper more than about 7 times by hand.
In space: light thins out as a⁴ (to the power 4). Grow the universe 2 times and light gets 2 × 2 × 2 × 2 = 16 times weaker.
How scientists write giant and tiny numbers
10³ means 10 × 10 × 10 = 1,000 (a 1 with 3 zeros). A minus sign flips it to a tiny number: 10⁻³ means one thousandth, 0.001.
Real world: 10⁶ is a million. So 3 × 10⁶ is just a short way of writing 3,000,000.
In space and quantum: the Planck constant ħ is about 1.05 × 10⁻³⁴. That's a decimal point followed by 33 zeros before the 1. Tiny, which is why we never notice quantum blur in everyday life.
The square root undoes squaring
If a square has an area of 25 tiles, its square root is the length of one side: 5. So √25 = 5, because 5 × 5 = 25.
Real world: you know your bedroom floor is 16 square metres and it's square. How long is each wall? √16 = 4 metres.
"÷ a³" means "spread out thinner as things grow"
Dividing by something big makes the answer small. When a formula divides by the size cubed, it means: the same stuff is being shared out over more and more room.
Real world: pour a spoon of squash into a small glass and it's strong. Pour the same spoon into a bucket and it's weak. Same squash, more room.
Omega just means "what share of the universe is this?"
Imagine the whole universe is a jar of 100 marbles, each colour for a different ingredient. Omega tells you how many marbles of each colour there are. The shares always add up to 1, the whole jar.
Radiation means light, and its share is tiny now
In cosmology, "radiation" means light and other things that zoom at (or almost at) the speed of light. Today it's only about 1 part in 10,000 of the universe. But when the universe was a baby, light was the boss.
Why it fades fastest: as space grows, light gets spread out (like matter does), AND each light wave gets stretched longer, so each bit of light carries less energy. Two kinds of fading at once: that's the a⁴.
Matter means stuff that has weight
Matter is all the stuff that pulls with gravity: stars, planets, people, gas, and also invisible "dark matter". Together they're about 31 or 32 marbles out of 100 (Ωm ≈ 0.315). Only about 5 of those are normal atoms; the rest is dark matter, which we only know about from its pull.
Why it fades: matter just gets spread out as space grows. Double the size, 8 times thinner: that's the a³.
Dark energy is a push that comes with space itself
Scientists think empty space has a little bit of energy built in. Make more space, you get more of that energy, so its strength per box never fades. Today it's the biggest share: about 69 marbles out of 100 (ΩΛ ≈ 0.685).
Like: a magic carpet that grows. However big the room gets, every square of floor still has the same carpet on it.
= is a balanced see saw, ≥ is a see saw that can't tip the other way
"=" means both sides weigh exactly the same. "≥" means the left side is at least as big as the right: it can be heavier, never lighter. "∝" means "goes up together with".
Real world: "your age ≥ 4" is true for everyone in your class. The rule doesn't say exactly how old, just never less than 4.
The letters that make formulas look scary
Scientists ran out of normal letters, so they borrowed Greek ones. They're just nicknames.
Little numbers at the bottom (like the ₀ in H₀) are labels, not maths: ₀ usually means "today's value".
The A to Z of this page
Anywhere on this page, a word with a dotted gold line under it can be tapped for a plain explanation. Here they all are in one place.
Why Ω and Λ mean different things in different places
Greek letters get reused, like nicknames. The subject you are reading tells you which meaning is meant.
Simple rule: on the cosmos pages, capital Λ is dark energy and Ω with a little label is a share. Anywhere else, check the subject first.
Decode any formula
Paste any formula, or a paragraph from a paper, into the Formula Decoder and it breaks it into these same building blocks with pictures.
The cosmos, one idea at a time
Nine ideas that unlock almost every space headline. Each one has a toy to play with.
Photony's story: how the cosmos works
Meet Photony, a tiny bit of light that has been flying for more than 13 billion years. Photony explains the Big Bang, the growing universe, the marble jar, stretched light and dark energy, with pictures timed to every word.
Looking far away means looking back in time
Light takes time to travel. So when you look at something far away, you see it as it was, not as it is.
Like getting a postcard: it tells you what the sender was doing when they wrote it, not now.
Speed of light c ≈ 299,792 km every second. A light year is how far light goes in a year, about 9.46 trillion km.
Space itself is stretching
Galaxies aren't flying through space. The space between them is growing, so everything moves apart.
Like raisins in rising bread dough: every raisin moves away from every other, and far raisins move away faster.
Speed away (km/s) = Hubble constant × distance (megaparsecs). One megaparsec (Mpc) ≈ 3.26 million light years. H₀ is "how fast space stretches today".
Stretched light turns redder
As light crosses stretching space, its waves get stretched too. Longer waves look redder. Stretch them enough and they become invisible infrared.
That's exactly why Webb sees in infrared: the first galaxies' light has been stretched out of the colours our eyes can see.
z is the redshift. When the light set off, the universe was 1 ÷ (1 + z) of its size today.
The Hubble tension
Measure how fast space stretches using the baby universe and you get about 67. Measure it using nearby stars and you get about 73. They should match. They don't.
Like two good stopwatches timing the same race and disagreeing by 10%. Either one is broken, or the race isn't what you thought.
A rough "age if expansion never changed". Units of H₀: km/s per Mpc. The real age (13.8 billion years) also depends on how expansion changed over time.
In the news: April 2026, 73.50 ± 0.81 from many independent methods, so it's not one bad ruler.
What are the four rows in the chart?
Four teams each measured the same number, H₀: how fast space is stretching today. You would expect them to agree. They don't.
- Planck (baby universe): 67.4. A space telescope mapped the leftover glow from when the universe was a baby. Scientists then work forward to predict today's stretching speed.
- SH0ES (stars and supernovae): 73.04. This team measures the nearby universe directly, using pulsing stars and exploding stars as distance markers, like mile posts along a road.
- H0DN 2026 (many methods): 73.5. A 2026 network of many separate distance rulers checked against each other. It lands at 73 too, so it is not one faulty ruler.
- Dark sirens 2026 (gravitational waves): 78.2. A new method that "hears" black holes crashing together as ripples in space. Its bar is very wide because only a few such events have been caught, so it cannot settle the question yet.
How to read it: the dot is each team's answer, the glowing bar is how unsure they are (short = very sure). The baby universe says about 67, the nearby universe says about 73. The bars don't overlap: either a measurement is off, or our picture of how the universe grew is missing something.
What "many methods" means: rulers for space
To measure how fast space stretches, you need two numbers for lots of galaxies: how fast each one is moving away (easy, from how red its light is) and how far away it is (hard). Each "method" is a different ruler for distance.
No single ruler reaches everywhere, so astronomers build a ladder. Each rung reaches further and is checked against the rung below.
The H0DN team (April 2026) wired these rulers into one network that checks them against each other: 73.50 ± 0.81. They also swapped in extra rulers as cross checks (other kinds of stars, other exploding stars, how fast galaxies spin) and the answer stayed around 73. So the gap from the baby universe's 67 is probably not a measuring mistake.
The mystery push
Since 1998 we've known the stretching is speeding up. We call whatever causes it "dark energy". The big question: is it a constant push, or does it change?
As the universe grows, matter spreads thinner. Constant dark energy doesn't. That's why it eventually wins.
a is the size of the universe (1 = today). Matter thins as a−3, light as a−4. Dark energy with w = −1 never thins: that's Einstein's cosmological constant. DESI's 2025 hint is that w isn't exactly −1.
ΩΛ: the universe's budget, and why expansion speeds up
Ω (Omega) means "what share of the universe is this ingredient?". ΩΛ (Omega Lambda) is dark energy's share. It is about 0.69, so roughly 69% of everything.
Think of the universe as a pie. All the slices together add up to 1, and that "1" means space is flat, like a sheet of paper rather than a ball.
Ω, Omega = "share of the budget". Scientists work out how much stuff the universe would need for space to be perfectly flat. They call that the critical amount (about 5 hydrogen atoms in every cubic metre). Each Ω says what fraction of that amount one ingredient supplies. Ω = 0.3 means "30% of the budget".
Λ, Lambda = "dark energy". Einstein added Λ to his equations in 1917 as a steady push built into empty space. Today it is the name for dark energy. Its key trick: every cubic metre of space holds the same amount, so when space grows, there is simply more of it.
The little labels just say which ingredient:
Read it out loud: "ΩΛ = 0.685" just means "dark energy is about 68.5% of the universe's budget". And ΩΛ + Ωm + Ωr ≈ 1 means "the slices fill the whole pie, so space is flat".
Values from the Planck satellite (2018). Elsewhere in science a small λ means a wave's length, but on this page Λ always means dark energy.
The thin end slice is everything made of atoms: stars, planets, you. Just 4.9%. Values from the Planck satellite.
That's the whole secret. As space grows, matter spreads out and its pull weakens, but dark energy doesn't fade. So about 6 billion years ago dark energy started winning, and the expansion began to speed up.
H is how fast space is stretching at any moment, H₀ is that speed today, and a is the size of the universe compared with now (a = 1 today, a = 0.5 when it was half the size).
Each term is one ingredient. Light (Ωr) is divided by a⁴, matter (Ωm) by a³, but ΩΛ is divided by nothing. That's why it ends up in charge.
critical density = 3H₀² ÷ 8πG ≈ 5 hydrogen atoms per m³Every Ω is "this ingredient ÷ the critical density". G is Newton's gravity constant.
speeding up when Ωm ÷ a³ < 2 × ΩΛWith Ωm = 0.315 and ΩΛ = 0.685 that happens at a ≈ 0.61, about 6.1 billion years ago. Today's "deceleration parameter" q₀ = Ωm ÷ 2 − ΩΛ ≈ −0.53. Negative means speeding up.
In the news: DESI's hint is that ΩΛ's ingredient might not be perfectly constant. See Idea 5's dial.
Gravity slows time down (really)
Clocks closer to heavy things tick slower. It's tiny on Earth, but real, and your phone's GPS has to correct for it every day.
Timescape cosmology takes this idea to a giant scale: clocks in crowded galaxies vs clocks in empty voids.
µs = millionths of a second. Light goes about 300 metres in one µs, so an uncorrected 38.5 µs a day becomes kilometres of position error.
Is it weird, or is it luck? (spinning galaxies)
If galaxies spin randomly, it's like flipping a coin for each one. The study saw about 2 out of 3 spinning one way. Is that too lopsided to be luck?
Flip 263 coins below, again and again, and see how often you get anything close to two thirds heads.
Two thirds is about 175, which is about 5 spreads away from 131.5. Pure luck almost never does that, so either something real is going on or the counting is biased (Shamir's own suggestion: our Milky Way's motion makes some galaxies look brighter).
Why "grown up" baby galaxies matter
Our model says early galaxies should be small and messy. Webb keeps finding some that are big and tidy (Big Wheel, the cluster XLSSC 122). One or two could be lucky. Lots would mean our model needs fixing.
Like finding a toddler who's six feet tall. One is a surprise. A whole nursery would rewrite the growth charts.
Has Webb debunked the Big Bang?
No. That is a popular headline, but not what the science says.
- Some galaxies look bigger and more grown up, earlier than expected. That challenges our ideas about how fast galaxies form, not whether there was a Big Bang. A very tall toddler changes the growth chart, not the fact that babies are born.
- Many early "impossible" galaxies were later scaled down: some were dusty, some had a bright black hole in the middle making them look heavier than they are.
- The main evidence for the Big Bang is untouched by Webb: the leftover heat glow from the early universe, galaxies moving apart, and the exact mix of hydrogen and helium in the oldest stars.
- A few scientists have proposed alternatives (one 2023 paper suggested a universe 26.7 billion years old). These are minority ideas that don't fit the other evidence well.
In short: the Big Bang stands, but the story of the first galaxies is being rewritten.
Quantum and CERN, made friendly
The tiny world plays by different rules. Here are six of them, with toys.
The pictures move on their own and loop. Charges are counted in "proton units": a proton is +1.
Atoms, charge and quarks, answered simply
What are protons, electrons and neutrons?
An atom is like a football stadium with a pea in the middle. The pea is the nucleus, made of protons and neutrons packed together. Electrons are like tiny flies buzzing around the stands.
- Proton: in the middle, charge +1. The number of protons decides what the stuff is: 1 is hydrogen, 6 is carbon, 8 is oxygen.
- Neutron: in the middle too, about the same weight as a proton but charge 0. It helps hold the middle together.
- Electron: whizzes around the outside, charge −1, about 1,836 times lighter than a proton. Electricity in a wire is electrons moving.
Why is the proton's charge called "1"?
It is just a choice. A proton and an electron carry exactly the same amount of charge, one plus and one minus. It is the smallest amount anything free carries, so scientists call it 1 and count in those units. Electrons ended up as "minus" because of a labelling choice Benjamin Franklin made in the 1700s, long before anyone knew electrons existed.
What is a coulomb?
A unit for charge, like a litre is a unit for water. One coulomb is the charge of about 6 billion billion protons. A phone charger at 1 amp pushes about 1 coulomb through the cable every second. One proton's charge is an incredibly tiny slice of a coulomb, which is why scientists prefer just saying "1".
Why do quarks have thirds of a charge?
Call a proton's charge 1 whole pizza, cut into 3 slices. An up quark (+⅔) brings 2 slices. A down quark (−⅓) owes 1 slice.
- Proton = up + up + down = 2 + 2 − 1 = 3 slices = 1 pizza.
- Neutron = up + down + down = 2 − 1 − 1 = 0 slices.
Quarks are never seen alone; they always group so the thirds add up to whole numbers.
"Pull a quark out and new quarks appear": is energy created from nothing?
No. Think of an elastic band holding two quarks. Pull them apart and the band stretches, storing your pulling energy. Before it lets go, that stored energy turns into a brand new quark and antiquark (E = mc²: energy can become matter). They grab the two loose ends, so you get two shorter bands instead of a free quark. All the energy is accounted for.
What makes a quark "up" or "down"?
Honestly, nobody knows the deeper reason. They are simply two different particles with different measured charge and weight (down is about twice as heavy). We know what they are, not why. One fact: a down can turn into an up by throwing out an electron and a ghostly antineutrino. That is how a neutron becomes a proton, a kind of radioactivity.
What are charm quarks and antiquarks?
There are 6 quarks in 3 pairs, each pair a heavier copy of the last: up and down (everyday), charm and strange, top and bottom. Charm is a heavier up: same +⅔ charge but nearly 600 times heavier, and it falls apart in about a trillionth of a second, so it only appears in places like CERN's collider. Antiquarks are mirror twins with the opposite charge: anti up is −⅔, anti down is +⅓. When a particle meets its twin, both vanish in a flash of light.
What do red, green and blue mean for quarks?
They are not real colours. They are labels for a second kind of charge that only quarks have, for the super strong glue force. Every group must "add up to white", like mixing red, green and blue light on a screen. A proton has one of each; a quark plus an antiquark works too (red + anti red = white).
Build a particle from quarks
Protons and neutrons are made of three smaller bits called quarks. Different recipes make different particles. In March 2026 CERN's LHCb found a new one: two charm quarks and a down quark.
Add up the three charges to get the particle's electric charge. Proton = u + u + d = ⅔ + ⅔ − ⅓ = +1.
What "sigma" means
Physicists say "5 sigma" before they call something a discovery. Sigma is a measure of how unlikely it is that a result is just a random fluke.
More sigma = more confident. 3 sigma is "interesting", 5 sigma is "discovery".
This counts flukes in either direction (two sided), the way the LHCb news quoted it.
Both at once, until you look
A quantum bit (qubit) can be in a mix of 0 and 1 at the same time. When you measure it, it picks one, with set odds.
Like a spinning coin: while it spins it's not heads or tails. Slap it down and it chooses.
|α|² is the chance of getting 0. The odds always add to 100%.
Two coins that always agree
Two particles can be linked so that measuring one instantly tells you about the other, however far apart they are. Each result on its own is random, but they always match.
You can't use it to send messages, because you can't choose your result. The 2022 Nobel Prize in Physics went to the experiments that proved it's real.
50% chance both are 0, 50% both are 1, 0% that they disagree (when measured the same way).
Pin it down here, it blurs over there
The more exactly you know where a particle is, the less exactly you can know how it's moving. Not because our tools are bad: it's how nature works.
Δx is the spread in position, Δp the spread in momentum, ħ is a tiny fixed number (reduced Planck constant).
Why things have mass
Space is filled with an invisible field, the Higgs field. Particles that "feel" it a lot become heavy; ones that don't, like light, have no mass. CERN found its particle, the Higgs boson, in 2012.
Like walking through a room full of fans: a celebrity gets mobbed and slowed down, a stranger walks straight through.
Quantum reality: what the strange experiments really mean
The double slit, Schrödinger's cat, Bohr against Einstein, what "observing" really means, and how quantum computers work. Each card has a "how sure" label.
One particle, two doors, a striped pattern
Fire tiny particles, one at a time, at a wall with two narrow slits. Each one lands as a single dot. But after thousands of dots, they make stripes, as if each particle went through both slits and met itself on the other side, like ripples in a pond.
Now put a detector at the slits to see which one each particle uses. The stripes vanish and you get two plain bands. Finding out the path changes the result.
λ is the wavelength, L the distance to the screen and d the gap between the slits. Particles have a wavelength too: λ = h ÷ (m × v), where h is Planck's constant, m the mass and v the speed. Heavier or faster particles have tinier waves, which is why big molecules are so hard to test.
How sure: rock solid. It has been done with light, electrons, atoms and even big molecules of over 2,000 atoms. Richard Feynman said it holds "the only mystery" of quantum physics.
The cat that was never meant to be taken seriously
In 1935 Erwin Schrödinger imagined a cat in a sealed box with a radioactive atom. If the atom decays, a detector breaks a bottle of poison. Quantum maths says the atom is in a mix of "decayed" and "not decayed" until it's measured. So, he joked, is the cat both alive and not alive until you open the box?
The twist: he meant it as a criticism. He thought it showed that applying quantum rules to everyday things sounds absurd. Today most physicists say the cat is never in a real mix: the atom bumping into the detector, the air and everything else settles things long before anyone looks. This settling is called decoherence.
The atom's state is a mix with two weights, a and b. The chance of each result is the weight squared: |a|² and |b|², and they always add up to 1. After one half life, both chances are ½.
How sure: decoherence is well tested in the lab. Exactly why we see one result and not another is still debated (see "What does observing mean?" below). No real cats are involved.
The greatest argument in physics, settled by experiment
Niels Bohr said that before you measure a particle, it truly has no definite answer: nature decides at random. Albert Einstein hated this. He wrote that God "does not play dice" and believed there must be hidden instructions we simply can't see yet.
- 1927: Bohr and Einstein argue at the Solvay conference in Brussels. Neither convinces the other.
- 1935: Einstein and two colleagues publish a paper arguing that entangled particles prove quantum theory is incomplete. Einstein later called entanglement "spooky action at a distance".
- 1964: John Bell finds a test. If hidden instructions exist, linked measurements can only agree up to a certain limit. Quantum theory predicts more.
- 1972 to 1998: John Clauser, Alain Aspect and Anton Zeilinger run the test. Quantum theory wins, again and again.
- 2015: the last loopholes are closed, for example by measuring particles 1.3 km apart before any signal could pass between them.
- 2022: Aspect, Clauser and Zeilinger win the Nobel Prize in Physics.
What it means: no simple hidden instructions can explain the results. Einstein was wrong about that, though his question pushed physics forward. Entangled pairs still can't be used to send messages faster than light.
S combines how often linked measurements agree at four detector settings (the CHSH version of Bell's test). Any "hidden instructions" theory can never get past 2. Real experiments land clearly above 2, as quantum theory predicts.
How sure: very sure. Nobel Prize 2022
No, you don't need a person looking
A big myth says quantum things change when a conscious person watches them. In physics, "observing" means any interaction that records information: a detector, a stray bit of air, a single photon bouncing off. A camera with nobody watching does the same job.
What nobody agrees on is why we get one answer and not the others. These are the main ideas. All of them predict the same results in today's experiments, which is why the argument isn't settled:
This is the Born rule. Quantum maths gives each result an amplitude, and the chance of seeing that result is its size squared. Every interpretation in the list above uses this same rule, which is why experiments can't pick between them yet.
How sure: the experiments are certain; what they mean is open. Physicists are split between these views.
Not "trying every answer at once"
A normal computer works with bits, each a 0 or a 1. A quantum computer uses qubits, which can be in a mix of 0 and 1, and can be entangled so they act as one linked system.
The real trick is interference. A quantum program is designed so the routes to wrong answers cancel out, like waves meeting crest to trough, and the routes to the right answer add up. When you measure, the right answer is the likely one. This only works for some special problems.
- Good at: simulating molecules and materials (new medicines, batteries, fertiliser), and some maths problems like factoring huge numbers.
- Not good at: everyday jobs. It won't make your phone, games or emails faster.
- The hard part: qubits are fragile, and any bump from the outside world spoils them (decoherence again). The fix is "error correction": spreading one reliable "logical" qubit across many physical ones. In December 2024 Google's Willow chip showed errors going down as it added more qubits, a long awaited milestone.
- Encryption: a big enough quantum computer could break the codes that protect online banking. In 2025 a Google researcher estimated this would need under a million physical qubits running for under a week. Today's machines are nowhere near that, and new "post quantum" codes, standardised by the US government in 2024, are already being rolled out.
10 qubits hold 1,024 amplitudes at once; 300 qubits hold more than there are atoms in the observable universe (2³⁰⁰ ≈ 2 × 10⁹⁰). For searching N items, Grover's method needs about √N steps instead of about N ÷ 2. For factoring big numbers, Shor's method is dramatically faster than any known normal method.
How sure: the physics is solid; the timelines are guesses. No quantum computer can break real encryption today. Google Willow · Encryption estimates, 2026
Want to read more? There's a book suggestion in the "Watch & read" tab.
Big questions: consciousness and the cosmos
Where physics meets the mind. These ideas are exciting, but most are not proven, so every card says plainly how sure we are.
Why does it feel like anything to be you?
Scientists can measure the electrical and chemical signals in your brain when you see red or feel happy. What nobody can explain yet is why those signals come with an inside feeling at all. Philosopher David Chalmers called this "the hard problem of consciousness" in 1995.
How sure: everyone agrees it's unsolved. Most neuroscientists expect the answer to come from ordinary brain activity, but nobody has shown how.
Could the mind be a quantum effect? (Orch OR)
In the 1990s, physicist Roger Penrose (who later won a Nobel Prize for work on black holes) and anaesthesiologist Stuart Hameroff proposed "Orchestrated Objective Reduction", or Orch OR. It says tiny tubes inside brain cells, called microtubules, hold quantum states, and each moment of awareness happens when one of those states collapses.
Penrose's rule: τ is how long a superposition lasts before it "picks", ħ is the reduced Planck constant and EG is the gravitational energy of the difference between the two states. Tegmark's 2000 estimate for the brain: quantum states fade in about 10⁻¹³ to 10⁻²⁰ seconds, while neurons work on about 10⁻³ seconds. That gap is the main objection.
How sure: a real but minority idea, with no conclusive evidence either way. Gran Sasso test · Rat study, 2024
Does your mind collapse the quantum world?
A popular claim says reality only "becomes real" when a conscious mind observes it. A few famous physicists played with this idea decades ago. Today almost all physicists reject it: detectors and even stray air molecules do the same job, with nobody watching.
How sure: very unlikely. See "What does observing mean?" in the Quantum reality tab.
Is everything a little bit aware? (Panpsychism)
Panpsychism is the idea that some simple form of experience is a basic feature of all matter, like mass or charge, and that brains combine it into full minds. Some go further and wonder whether the universe as a whole is conscious.
It's taken seriously by some philosophers because it avoids the hard problem. Its own puzzle is how tiny bits of experience would combine into one mind. Right now there is no experiment that could test it.
How sure: philosophy, not physics. Interesting, untested, and currently untestable.
What physics does say for certain
Apart from hydrogen, which dates from the Big Bang, almost every atom in your body was made inside stars and spread by exploding or colliding stars billions of years ago. In a very real sense, you are a part of the universe that can look at itself and ask questions. That part is not speculation.
In a star's core, four hydrogen nuclei fuse into one helium nucleus. The helium weighs about 0.7% less than the four hydrogens, and that missing mass becomes energy. Heavier elements like carbon and oxygen are built in later stages, and the heaviest in exploding and colliding stars.
How sure: rock solid. The carbon, oxygen, calcium and iron in you were all made in stars.
Latest research, explained
A new plain English digest is added every week. Each result gets a "how sure" label, so you know what's solid and what's a hint.
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New papers this week
Pulled automatically from arXiv, where physicists post papers first. These are raw titles, not yet explained.
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Photony's story: how the cosmos works
Meet Photony, a tiny bit of light that has been flying for more than 13 billion years. Photony explains the Big Bang, the growing universe, the marble jar, stretched light and dark energy, with pictures timed to every word.
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