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

Tariffs Explained: I Have Everything You Need to Know as Trump Spars With Apple, Walmart

Technologies

How Much Will the iPhone 17 Cost?

Tariffs could hike the price of the new iPhone, but other factors play a role, too. What to look for as the release day approaches.

The rumored iPhone 17 is getting plenty of attention for potential new features and upgrades, like more memory and a camera upgrade. And the prospect of an ultrathin iPhone just adds to the excitement as the expected release date approaches.

But of all the rumors about the new iPhone, one of the most persistent may be: How much will it cost?

There are a lot of factors that could affect the pricing for the rumored iPhone 17, including tariffs, production costs and the overall health of the US economy.

Apple did not respond to a request for comment.

We won’t know the exact price for the next iPhone until its release, which is expected to be in September. But we’ve pored over all the leaks, rumors and predictions about prices, and we found ways to help you save if a new iPhone is in your future.

How tariffs could affect the cost of the next iPhone

Amid President Donald Trump’s ongoing tariff bender, higher reciprocal tariffs are currently on pause. However, Trump took to social media on Friday, threatening Apple with a 25% tariff on all iPhones made outside the US. While there’s no timeline for this tariff rollout, there’s currently a 10% baseline tariff on all imports and a 30% tariff on goods from China, where Apple still manufactures most of its products. Those rates may also start to rise in July when the initial tariff pause expires, which could lead to higher prices on everything — including the rumored iPhone 17.

Apple appears to have dodged a lot of the initial tariff impact. It stockpiled phones before tariffs took effect, and Trump’s exemption list included many phones, laptops and other electronics that Apple produces.

The tech giant has also moved some US iPhone production from China to India, which currently has a lower tariff rate. However, Trump called out Apple CEO Tim Cook to instead move iPhone production to the US. Most experts consider this an unrealistic demand, especially in the short term, because of higher labor and production costs in the US. Estimates have suggested that a US-made iPhone would cost as much as $3,500.

That leaves prices for the next iPhone in limbo. Trump’s administration called the exemption list «temporary» in early April, saying that exemptions would end in «a month or two.» Around the same time, Trump said that semiconductors, which power tech products, will eventually be placed in a different «tariff bucket.» However, no details have been shared about the timeline or expected tariff percentages.

With all the reprieves appearing to be temporary, tariffs could still potentially affect prices by the time the rumored iPhone 17 is expected to be released.

If the original reciprocal tariff pause expires, for instance, taxes on imports from India would rise from 10% to 26% starting in July. If the 90-day pause for China expires, tariffs on that country would jump from 30% to 145% in August. Experts point out that a tariff rate hike doesn’t necessarily mean an iPhone’s price would increase at the same rate, but most expect at least some impact.

And where the phone is assembled is only part of the tariff equation. Apple sources components for the iPhone from dozens of other countries, which could also potentially affect the price.

Based on where tariffs stand now, here’s how much you could potentially pay for the next iPhone based on current iPhone 16 prices. These are estimates and not pricing from Apple:

How much could tariffs affect the price of an iPhone 17?*

	Current price	Current 10% tariff on goods from India	Potential 26% tariff for India	Current 30% tariff on goods from China	Potential 145% tariff for China
iPhone 16E (128GB)	$599	$659	$830	$779	$1,614
iPhone 16 (128GB)	$799	$879	$1,107	$1,039	$2,153
iPhone 16 Plus (128GB)	$899	$989	$1,246	$1,169	$2,423
iPhone 16 Pro (128GB)	$999	$1,099	$1,385	$1,299	$2,692
iPhone 16 Pro Max (256GB)	$1,199	$1,319	$1,662	$1,559	$3,231
iPhone 16 Pro Max (1TB)	$1,599	$1,759	$2,216	$2,079	$4,309

*Trump’s newly proposed 25% Apple tariff on iPhones manufactured outside the US could further increase the price of the next iPhone. We’ll keep this story up to date with the latest pricing information as we receive it.

What else could cause the new iPhone’s price to increase?

Trump immediately criticized retailers like Walmart and Amazon when they suggested that tariffs could result in higher prices, so it stands to reason that Apple won’t directly blame tariffs for potential price hikes to avoid a Trump tirade.

Rather, Apple could attribute the price increase to improved features and design costs. Regardless of tariffs, Apple has plans to raise iPhone prices this year, The Wall Street Journal reported.

Experts say Apple may be overdue for a price increase anyways. It’s been five years since the basic iPhone model increased in price, and each iteration of the iPhone generally improves on features from the last version.

My colleague Patrick Holland, CNET’s managing editor, has been reviewing phones for CNET since 2016 and tracking prices over the years. He notes that the base iPhone model hasn’t gone up in price since 2020.

His research points to the standard iPhone model’s price increasing approximately every five years, typically between $50 and $150. Based on this evidence and the iPhone 16’s current price of $799, we could expect the new iPhone to cost somewhere between $850 and $950.

What will the iPhone 17 Air cost?

Early rumors had the iPhone 17 Air topping the iPhone Pro in price. However, a March Bloomberg report suggested the phone could cost around $900, similar to the current iPhone 16 Plus’s price tag. Those estimates are based on the current costs and may not include the potential impact tariffs could have on an ultrathin iPhone’s price.

How the economy could affect iPhone prices

Uncertainty in the US economy — in part due to the aforementioned tariff turmoil — has left many wary about what’s to come. While the recent agreement with China to pause tariffs helped the stock market to mostly recover from the dive it took after Trump’s Liberation Day, that reprieve offers only temporary relief.

Concerns about the risks of higher unemployment and higher inflation have left the Federal Reserve in wait-and-see mode for lowering interest rates. Higher interest rates can cause companies like Apple to pull back on spending and investment. Combined with higher tariffs, that pullback could potentially lead to global supply chain disruptions. Fewer iPhones available in the market could lead to higher prices.

If inflation resurges, rising costs could force Apple to increase the next iPhone’s price.

One tiny bright side, in theory, is that a weakening economy could force Apple to hold off on raising prices so it can stay competitive. But that may not offer much consolation if you’re worried about spending money because of a potential recession.

Will older iPhones cost more, too?

One way to save on Apple products is to buy last year’s model instead of the newest release. However, if the new iPhone is dramatically more expensive when it’s released, demand could increase for the older models. That could lead to price hikes on older models, too.

The flip side of this is that if the new iPhone’s prices rise and you have an older iPhone, your old iPhone would also likely increase in value, Holland said.

Trading or selling a used iPhone can help offset the cost if you do decide to buy the new iPhone.

Other ways Apple could raise prices

Even if Apple decides to hold the next iPhone’s price steady, there are other ways for the tech giant to recoup increased costs.

Apple could potentially offset the impact of tariffs by raising the price on its services — including its music, news and data plans — according to supply chain expert Joe Hudicka.

«We’ll see those markups in the subscription services first because they’ll appear smaller,» he said. «Consumers will still pay, just not all at once.»

Should we believe rumors and speculation about iPhone prices?

So seriously, how much is a new iPhone going to cost? The truth is, we can’t say with any certainty what the final numbers will be. Our assessments are based on ever-changing tariff policies, past pricing trends, rumors and leaks that are sometimes based on insider knowledge. But until Apple releases the rumored iPhone 17, we can only offer our best estimates for how much the final price tag will be.

Technologies

Today’s NYT Mini Crossword Answers for Saturday, May 24

Here are the answers for The New York Times Mini Crossword for May 24.

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

No matter how many NYT Mini Crossword puzzles I’ve done, those double-meaning clues always trip me up. So I see 8-Across, «army shirt,» and am trying to make «khaki» or «camo» fit. And I see 10-across, «wand-waving org,» and my mind goes to Harry Potter. I was wrong on both. Need some help with today’s Mini Crossword? Read on. And if you could use some hints and guidance for daily solving, check out our Mini Crossword tips.

The Mini Crossword is just one of many games in the Times’ games collection. If you’re looking for today’s Wordle, Connections, Connections: Sports Edition and Strands answers, you can visit CNET’s NYT puzzle hints page.

Read more: Tips and Tricks for Solving The New York Times Mini Crossword

Let’s get at those Mini Crossword clues and answers.

Mini across clues and answers

1A clue: «Get a load of ___!»
Answer: THIS

5A clue: Ability to keep one’s balance on a ship
Answer: SEALEGS

8A clue: Army shirt?
Answer: TANKTOP

9A clue: Chicago trains
Answer: ELS

10A clue: Wand-waving org.
Answer: TSA

11A clue: Flowers depicted in classical Chinese art
Answer: PEONIES

13A clue: By oneself
Answer: ALONE

14A clue: Phileas ___, «Around the World in Eighty Days» protagonist
Answer: FOGG

Mini down clues and answers

1D clue: Something «read» in the divination method of tasseography
Answer: TEALEAF

2D clue: Sci-fi hero with the line «Never tell me the odds»
Answer: HANSOLO

3D clue: Kind
Answer: ILK

4D clue: Where a story takes place
Answer: SETTING

5D clue: Lather, rinse or repeat
Answer: STEP

6D clue: «Take a look for yourself!»
Answer: GOSEE

7D clue: Places to get pampered
Answer: SPAS

12D clue: Eggy holiday drink
Answer: NOG

How to play more Mini Crosswords

The New York Times Games section offers a large number of online games, but only some of them are free for all to play. You can play the current day’s Mini Crossword for free, but you’ll need a subscription to the Times Games section to play older puzzles from the archives.