Technologies

What Is Dark Matter? The Answer to Universe’s Greatest Mystery Could Be Axions

The saga of how an odd hypothetical particle became a star dark matter candidate.

Physics is permeated by conundrums, and in a sense, that’s what keeps the field going. These mind-bending puzzles foster a race toward truth. But of all the dilemmas, I’d say two of them unquestionably fall under priority A.

First off, when scientists look up at the sky, they consistently see stars and galaxies traveling farther from our planet, and from each other, in every direction. The universe kind of looks like a bubble blowing up, which is how we’ve come to know it’s expanding. But something doesn’t make sense.

Space doesn’t seem to have enough stuff floating around in it — stars, particles, planets and all else — for it to inflate so swiftly. In other words, the universe is expanding way faster than our physics says it can, and it’s even picking up speed as you read this. Which brings us to problem two.

Per experts’ best calculations, galaxies are spinning so incredibly quickly as everything zips around that we’d expect the spirals to behave like out-of-control merry-go-rounds flinging metal horses off the ride. There doesn’t seem to be enough stuff in the universe to anchor them together. Yet the Milky Way isn’t drifting apart.

So… what’s going on?

As blanket terms, physicists call «missing» stuff pushing the cosmos outward dark energy, and pieces holding galaxies together — presumably in a halo-like form — dark matter. Neither interacts with light or matter we can see, so they’re essentially invisible. Combined, dark matter and dark energy make up a whopping 95% of the universe.

Zeroing in on dark matter’s portion, the authors of a recent review, published in the journal Science Advances, write that «it may well consist of one or more types of fundamental particle … although part or all of it might consist of macroscopic lumps of some invisible form of matter, such as black holes.»

Black holes or not, dark matter is totally elusive. In an effort to decode its secrets, scientists have picked a handful of suspects out of the cosmic lineup, and one of the most wanted particles is an odd little speck called the axion.

The wide-eyed hypothesis of axions

You might’ve heard of the Standard Model, which is pretty much the holy grail, ever-strengthening handbook of particle physics. It outlines how every single particle in the universe works.

However, as the Science Advances review points out, some «particle physicists are restless and dissatisfied with the Standard Model because it has many theoretical shortcomings and leaves many pressing experimental questions unanswered.» More specifically for us, it leads right into a paradox regarding a well-established scientific concept dubbed CPT invariance. Aha, the physics puzzles continue.

Basically, CPT invariance states that the universe must be symmetrical when it comes to C (charge), P (parity) and T (time). For that reason, it’s also called CPT symmetry. If everything had the opposite charge, was left-handed instead of right-handed and traveled through time backward instead of forward, it states the universe should remain just the same.

For a long while, CPT symmetry seemed unbreakable. Then 1956 came around.

Long story short, scientists found something that violates the P part of CPT symmetry. It’s called the weak force, and it dictates things like neutrino collisions and element fusion in the sun. Everyone was shocked, confused and scared.

Nearly every foundational concept of physics relies on CPT symmetry.

About a decade later, researchers discovered the weak force violating C symmetry, too. Things were falling apart. Physicists could just hope and pray that even if P is violated… and CP is violated… maybe CPT still isn’t. Maybe weak forces just need the trio to uphold CPT symmetry. Thankfully, this theory seems correct. For some unknown reason, the weak force follows total CPT symmetry despite C and CP blips. Phew.

But here’s the issue. If weak forces violate CP symmetry, you’d expect strong forces to as well, right? Well, they don’t, and physicists don’t know why. This is called the strong CP problem — and precisely where things get interesting.

Neutrons — uncharged particles within atoms — abide by the strong force. Plus, allowing for simplification, their neutral charge means they violate T symmetry. And «if we find something that violates T symmetry, then it must also violate CP symmetry in such a way that the combination CPT is not violated,» the paper states. But… that’s weird. Neutrons don’t because of the strong CP problem.

And so the idea of the axion was born.

Years ago, physicists Roberto Peccei and Helen Quinn suggested adding a new dimension to the Standard Model. It involved a field of ultralight particles — axions — that explained the strong CP problem, thereby relaxing the conditions for neutrons. Axions appeared to fix everything so well that the duo’s idea became the «most popular solution to the strong CP problem,» the paper states. It was a miracle.

To be clear, axions are still hypothetical, but think about what just happened. Physicists added a new particle to the Standard Model, which outlines specks of the entire universe. What might that mean for everything else?

The key to dark matter?

Per the Peccei-Quinn theory, axions would be «cold,» or very slowly moving through space. And… the study researchers say «the existence of [dark matter] is inferred from its gravitational effects, and astrophysical observations suggest that it is ‘cold.'»

The paper also states, «there are experimental upper limits on how strongly [the axion] interacts with the visible matter.»

So, basically, axions that help explain the strong CP problem also seem to have theoretical properties that align with those of dark matter. Extremely well.

The European Council for Nuclear Research, better known as CERN, which runs the Large Hadron Collider and is leading the charge for antimatter studies, also underlines «one of the most suggestive properties of axions is that, in a natural way, they could be produced in huge numbers soon after the Big Bang. This population of axions would still be present today and could compose the dark matter of the universe.»

There you go. Axions are among the hottest topic in physics because they seem to explain so much. But once again, those sought-after bits are still hypothetical.

Will we ever find axions?

It’s been 40 years since scientists began hunting for axions.

Most of these searches are «mainly exploiting the action field interaction with the electromagnetic fields,» say the authors in that recent review published in Science Advances.

For instance, CERN developed the Axion Search Telescope, a machine built to find a hint of the particles produced in the sun’s core. Inside our star, there are strong electric fields that could potentially interact with axions — if they’re really there, that is.

But the quest has so far faced a few pretty big challenges. For one, «the particle mass is not theoretically predictable,» the authors write — that is, we have very little idea of what an axion might look like.

Right now, scientists are still searching for them while assuming a vastly wide range of masses. Recently, however, researchers offered evidence that the particle is likely between 40 and 180 microelectron volts. That’s unthinkably small, at about 1 billionth the mass of an electron.

«In addition,» the team writes, «the axion signal is expected to be very narrow … and extremely feeble due to very weak couplings to Standard Model particles and fields.» In essence, even if minuscule axions try their very best to signal their existence to us, we might miss them. Their cues could be so weak we’d barely notice.

Despite these hurdles, the axion search marches on. Most scientists argue that they must be out there somewhere but they seem too good to be true when it comes to fully explaining dark matter.

«Most experimental attempts assume that axions compose 100% of the dark matter halo,» the study authors emphasize, suggesting that perhaps there’s a way to «look into axion physics without relying on such an assumption.»

Though they may be the star of the show, what if axions are just one chapter of dark matter history?

Technologies

The Future’s Here: Testing Out Gemini’s Live Camera Mode

Gemini Live’s new camera mode feels like the future when it works. I put it through a stress test with my offbeat collectibles.

«I just spotted your scissors on the table, right next to the green package of pistachios. Do you see them?»

Gemini Live’s chatty new camera feature was right. My scissors were exactly where it said they were, and all I did was pass my camera in front of them at some point during a 15-minute live session of me giving the AI chatbot a tour of my apartment. Google’s been rolling out the new camera mode to all Android phones using the Gemini app for free after a two-week exclusive to Pixel 9 (including the new Pixel 9A) and Galaxy S5 smartphones. So, what exactly is this camera mode and how does it work?

When you start a live session with Gemini, you now how have the option to enable a live camera view, where you can talk to the chatbot and ask it about anything the camera sees. Not only can it identify objects, but you can also ask questions about them — and it works pretty well for the most part. In addition, you can share your screen with Gemini so it can identify things you surface on your phone’s display.

When the new camera feature popped up on my phone, I didn’t hesitate to try it out. In one of my longer tests, I turned it on and started walking through my apartment, asking Gemini what it saw. It identified some fruit, ChapStick and a few other everyday items with no problem. I was wowed when it found my scissors.

That’s because I hadn’t mentioned the scissors at all. Gemini had silently identified them somewhere along the way and then recalled the location with precision. It felt so much like the future, I had to do further testing.

My experiment with Gemini Live’s camera feature was following the lead of the demo that Google did last summer when it first showed off these live video AI capabilities. Gemini reminded the person giving the demo where they’d left their glasses, and it seemed too good to be true. But as I discovered, it was very true indeed.

Gemini Live will recognize a whole lot more than household odds and ends. Google says it’ll help you navigate a crowded train station or figure out the filling of a pastry. It can give you deeper information about artwork, like where an object originated and whether it was a limited edition piece.

It’s more than just a souped-up Google Lens. You talk with it, and it talks to you. I didn’t need to speak to Gemini in any particular way — it was as casual as any conversation. Way better than talking with the old Google Assistant that the company is quickly phasing out.

Google also released a new YouTube video for the April 2025 Pixel Drop showcasing the feature, and there’s now a dedicated page on the Google Store for it.

To get started, you can go live with Gemini, enable the camera and start talking. That’s it.

Gemini Live follows on from Google’s Project Astra, first revealed last year as possibly the company’s biggest «we’re in the future» feature, an experimental next step for generative AI capabilities, beyond your simply typing or even speaking prompts into a chatbot like ChatGPT, Claude or Gemini. It comes as AI companies continue to dramatically increase the skills of AI tools, from video generation to raw processing power. Similar to Gemini Live, there’s Apple’s Visual Intelligence, which the iPhone maker released in a beta form late last year.

My big takeaway is that a feature like Gemini Live has the potential to change how we interact with the world around us, melding our digital and physical worlds together just by holding your camera in front of almost anything.

I put Gemini Live to a real test

The first time I tried it, Gemini was shockingly accurate when I placed a very specific gaming collectible of a stuffed rabbit in my camera’s view. The second time, I showed it to a friend in an art gallery. It identified the tortoise on a cross (don’t ask me) and immediately identified and translated the kanji right next to the tortoise, giving both of us chills and leaving us more than a little creeped out. In a good way, I think.

I got to thinking about how I could stress-test the feature. I tried to screen-record it in action, but it consistently fell apart at that task. And what if I went off the beaten path with it? I’m a huge fan of the horror genre — movies, TV shows, video games — and have countless collectibles, trinkets and what have you. How well would it do with more obscure stuff — like my horror-themed collectibles?

First, let me say that Gemini can be both absolutely incredible and ridiculously frustrating in the same round of questions. I had roughly 11 objects that I was asking Gemini to identify, and it would sometimes get worse the longer the live session ran, so I had to limit sessions to only one or two objects. My guess is that Gemini attempted to use contextual information from previously identified objects to guess new objects put in front of it, which sort of makes sense, but ultimately, neither I nor it benefited from this.

Sometimes, Gemini was just on point, easily landing the correct answers with no fuss or confusion, but this tended to happen with more recent or popular objects. For example, I was surprised when it immediately guessed one of my test objects was not only from Destiny 2, but was a limited edition from a seasonal event from last year.

At other times, Gemini would be way off the mark, and I would need to give it more hints to get into the ballpark of the right answer. And sometimes, it seemed as though Gemini was taking context from my previous live sessions to come up with answers, identifying multiple objects as coming from Silent Hill when they were not. I have a display case dedicated to the game series, so I could see why it would want to dip into that territory quickly.

Gemini can get full-on bugged out at times. On more than one occasion, Gemini misidentified one of the items as a made-up character from the unreleased Silent Hill: f game, clearly merging pieces of different titles into something that never was. The other consistent bug I experienced was when Gemini would produce an incorrect answer, and I would correct it and hint closer at the answer — or straight up give it the answer, only to have it repeat the incorrect answer as if it was a new guess. When that happened, I would close the session and start a new one, which wasn’t always helpful.

One trick I found was that some conversations did better than others. If I scrolled through my Gemini conversation list, tapped an old chat that had gotten a specific item correct, and then went live again from that chat, it would be able to identify the items without issue. While that’s not necessarily surprising, it was interesting to see that some conversations worked better than others, even if you used the same language.

Google didn’t respond to my requests for more information on how Gemini Live works.

I wanted Gemini to successfully answer my sometimes highly specific questions, so I provided plenty of hints to get there. The nudges were often helpful, but not always. Below are a series of objects I tried to get Gemini to identify and provide information about.

Technologies

Today’s Wordle Hints, Answer and Help for April 26, #1407

Here are hints and the answer for today’s Wordle No. 1,407 for April 26. Hint: Fans of a certain musical group will rock out with this puzzle.

Looking for the most recent Wordle answer? Click here for today’s Wordle hints, as well as our daily answers and hints for The New York Times Mini Crossword, Connections, Connections: Sports Edition and Strands puzzles.

Today’s Wordle puzzle isn’t too tough. The letters are fairly common, and fans of a certain rock band might get a kick out of the answer. If you need a new starter word, check out our list of which letters show up the most in English words. If you need hints and the answer, read on.

Today’s Wordle hints

Before we show you today’s Wordle answer, we’ll give you some hints. If you don’t want a spoiler, look away now.

Wordle hint No. 1: Repeats

Today’s Wordle answer has no repeated letters.

Wordle hint No. 2: Vowels

There is one vowel in today’s Wordle answer.

Wordle hint No. 3: Start letter

Today’s Wordle answer begins with the letter C.

Wordle hint No. 4: Rock out

Today’s Wordle answer is the name of a legendary English rock band.

Wordle hint No. 5: Meaning

Today’s Wordle answer can refer to a violent confrontation.

TODAY’S WORDLE ANSWER

Today’s Wordle answer is CLASH.

Yesterday’s Wordle answer

Yesterday’s Wordle answer, April 25, No. 1406 was KNOWN.

Recent Wordle answers

April 21, No. 1402: SPATE

April 22, No. 1403: ARTSY

April 23, No. 1404: OZONE.

April 24, No. 1405: GENIE

What’s the best Wordle starting word?

Don’t be afraid to use our tip sheet ranking all the letters in the alphabet by frequency of uses. In short, you want starter words that lean heavy on E, A and R, and don’t contain Z, J and Q.

Some solid starter words to try:

ADIEU

TRAIN

STARE

NOISE

Technologies

T-Mobile Adds New Top 5G Plans, T-Satellite and New 5-Year Price Locks

The new top unlimited plans, Experience More and Experience Beyond, shave some costs and add data and satellite options.

Just two years after expanding its lineup of cellular plans, T-Mobile this week announced two new plans that replace its Go5G Plus and Go5G Next offerings, refreshed its prepaid Metro line and wrapped them all in a promised five-year pricing guarantee.

To convert more subscribers, the carrier is also offering up to $800 to help customers pay off phone balances when switching from another carrier.

In a briefing with CNET, Jon Friar, president of T-Mobile’s consumer group, explained why the company is revamping and simplifying its array of mobile plans. «The pain point that’s out there over the last couple of years is rising costs all around consumers,» Friar said. «For us to be able to bring more value and even lower prices on [plans like] Experience More versus our former Go5G Plus is a huge win for consumers.»

The new plans went into effect April 23.

With these changes, CNET is already hard at work updating our picks for Best T-Mobile Plans, so check back soon for our recommendations.

More Experiences to define the T-Mobile experience

The top of the new T-Mobile postpaid lineup is two new plans: Experience More and Experience Beyond.

Experience More is the next generation of the Go5G Plus plan, which has unlimited 5G and 4G LTE access and unlimited Premium Data (download speeds up to 418Mbps and upload speeds up to 31Mbps). High-speed hotspot data is bumped up to 60GB from 50GB per month. The monthly price is now $5 lower per line than Go5G Plus.

The Experience More plan also gets free T-Satellite with Starlink service (the new name for T-Mobile’s satellite feature that uses Starlink’s constellation of satellites) through the end of 2025. Although T-Satellite is still officially in beta until July, customers can continue to get free access to the beta starting now. At the start of the new year, the service will cost $10 per month, a $5 drop from T-Mobile’s originally announced pricing. T-Satellite will be open to customers of other carriers for the same pricing beginning in July.

The new top-tier plan, Experience Beyond, also comes in $5 per line cheaper than its predecessor, Go5G Next. It has 250GB of high-speed hotspot data per month, up from 50GB, and more data when you’re traveling outside the US: 30GB in Canada and Mexico (versus 15GB) and 15GB in 215 countries (up from 5GB). T-Satellite service is included in the Experience Beyond plan.

However, one small change to the Experience plans affects that pricing: Taxes and fees, previously included in the Go5G Plus and Go5G Next prices, are now broken out separately. T-Mobile recently announced that one such fee, the Regulatory Programs and Telco Recovery Fee, would increase up to 50 cents per month.

According to T-Mobile, the Experience Beyond rates and features will be «rolling out soon» for customers currently on the Go5G Next plan.

The Essentials plan is staying in the lineup at the same cost of $60 per month for a single line, the same 50GB of Premium Data and unlimited 5G and 4G LTE data. High-speed hotspot data is an optional $10 add-on, as is T-Satellite access, for $15 (both per month).

Also still in the mix is the Essentials Saver plan, an affordable option that has ranked high in CNET’s Best Cellphone Plans recommendations.

Corresponding T-Mobile plans, such as those for military, first responders and people age 55 and older are also getting refreshed with the new lineup.

T-Mobile’s plan shakeup is being driven in part by the current economic climate. Explaining the rationale behind the price reductions and the streamlined number of plans, Mike Katz, president of marketing, innovation and experience at T-Mobile told CNET, «We’re in a weird time right now where prices everywhere are going up and they’ve happened over the last several years. We felt like there was an opportunity to compete with some simplicity, but more importantly, some peace of mind for customers.»

Existing customers who want to switch to one of the new plans can do so at the same rates offered to new customers. Or, if a current plan still works for them, they can continue without changes (although keep in mind that T-Mobile earlier this year increased prices for some legacy plans).

Five years of price stability

It’s nearly impossible to think about prices these days without warily eyeing how tariffs and US economic policy will affect what we pay for things. So it’s not surprising to see carriers implement some cost stability into their plans. For instance, Verizon recently locked prices for three years on their plans.

Now, T-Mobile is building a five-year price guarantee for its T-Mobile and Metro plans. That pricing applies to talk, text and data amounts — not necessarily taxes and other fees that can fluctuate.

Given the uncertain outlook, it seems counterintuitive to lock in a longer rate. When asked about this, Katz said, «We feel like our job is to solve pain points for customers and we feel like this helps with this exact sentiment. It shifts the risk from customers to us. We’ll take the risk so they don’t have to.»

The price hold applies to new customers signing up for the plans as well as current customers switching to one. T-Mobile is offering the same deals and pricing to new and existing subscribers. Also, the five-year deal applies to pricing; it’s not a five-year plan commitment.

More money and options to encourage switchers

The promise of a five-year price guarantee is also intended to lure people from other carriers, particularly AT&T and Verizon. As further incentive, T-Mobile is offering up to $800 per line (distributed via a virtual prepaid Mastercard) to help pay off other carriers’ device contracts. This is a limited-time offer. There are also options to trade in old devices, including locked phones, to get up to four new flagship phones.

Or, if getting out of a contract isn’t an issue, T-Mobile can offer $200 in credit (up to $800 for four lines) to bring an existing number to the network.

Four new Metro prepaid plans

On the prepaid side, T-Mobile is rolling out four new Metro plans, which are also covered by the new five-year price guarantee:

• Metro Starter costs $25 per line per month for a family of four and there is no need to bring an existing number. (The cost is $105 the first month.)

• Metro Starter Plus runs $40 per month for a new phone, unlimited talk, text and 5G data when bringing an existing number. For $65 per month, new customers can get two lines and two new Samsung A15 phones. No autopay is required.

• Metro Flex Unlimited is $30 per line per month with autopay for four lines ($125 the first month) with unlimited talk, text and 5G data.

• Metro Flex Unlimited Plus costs $60 per line per month, then $35 for lines two and three and then lowers the price of the fourth line to $10 per month as more family members are added. Adding a tablet or smartwatch to an existing line costs $5. And streaming video, such as from the included Amazon Prime membership, comes through at HD quality.

See more: If you’re looking for phone plans, you may also be looking for a new cell phone. Here are CNET’s picks.