Here’s what happened in the impact crater the day it did in the dinos 0 63

Here’s what happened in the impact crater the day it did in the dinos

The day it went down —

Rock core allows researchers to create an incredible timeline.


Industrial ocean platform.

Enlarge / This is “Liftboat Myrtle,” which housed the drilling operation into Chicxulub Crater.

Geology is a big science. The Earth is a large enough place today, but when you stretch the fourth dimension back across many millions of years, the largeness can get out of hand. Because we lose a lot of detail to the ravages of time, it’s very difficult for geology to get small again—to tell us about what happened in individual locations or over short periods of time.

So it’s not every day that you read a scientific paper titled “The first day of the Cenozoic.” The Cenozoic is the name geologists give to the era spanning the last 66 million years, and it started with the mass extinction event that killed off (most of) the dinosaurs. There were incredible eruptions that contributed to the extinction event and spanned a considerable amount of time.

But the asteroid that struck off the coast of what is the Yucatán Peninsula today was the opposite—it couldn’t have been much more sudden. A recent drilling project recovered a long core of rock from the Chicxulub impact crater, leading to greater clarity about how the calamity played out—including on that first day.

Big enough impact craters actually have a knob of uplifted rock in the center that forms due to the incredible shock forces involved. But the very largest impacts—like Chicxulub—end up with a ring of uplifted rock around the center, as if to mark the bulls-eye. Computer modeling, supported by observations of the deepest bedrock in the core, shows that the rock would have bounced around like jelly. Over 10 minutes or so, a new mountain would have soared into the sky before collapsing and spreading out into a raised ring on the crater floor.

Higher up in the core, a layer of seafloor sediment seems to record a miraculous return of small critters to the crater within just a couple years.

Between the jellified granite and the brave plankton fossils lies about 130 meters of chaotic rock. A team of researchers led by the University of Texas at Austin’s Sean Gulick have analyzed that rock and produced a timeline of that impossibly violent day. They threw just about every tool available at the rock core, including X-ray techniques that image it and identify minerals, to a machine-learning analysis that identified trends in the visible shards of rock, to measurements of magnetism.

The first layer above the messed-up bedrock that formed the peak ring is made up of 40m of broken pieces of melted rock. The researchers say this material was likely flowing out from the center of the crater for some tens of minutes after the impact. It settled into place while it was still hot, and the tiny crystals of magnetite in this rock are all aligned with Earth’s magnetic field at that time.

Here's the timeline of events recorded inside the impact crater.

Enlarge / Here’s the timeline of events recorded inside the impact crater.

The next layer up contains about 10m of pieces of melt in addition to shocked bedrock that was blasted out (roughly) intact. The researchers say this actually appears to be the first part of the “resurge” deposit—material that flowed with seawater as it rushed back into the crater and over the peak ring. Modeling shows that the tsunami generated during the impact would have bounced off the nearest Central American coastline and returned in about an hour. Apart from pushing stuff around, this water probably also caused some explosions as it encountered still-hot melted rock.

The next 80m of rock up from there show the first signs of order. From the bottom of this layer toward the top, the pieces get smaller and less jagged, indicating that tumbled rocks and sediment were more gradually settling out of the water column. This is topped off by a 10cm-thick layer of sand and gravel deposited in ripples, indicating a flow of water with a consistent direction. The researchers interpret this as a later tsunami wave return from the Gulf of Mexico several hours after impact.

The uppermost materials contain combustion byproducts called PAHs and even some charcoal, which likely represents residue from wildfires on land. It’s believed that the impact may have started wildfires worldwide, contributing to the particulate matter that blocked out the Sun and sent temperatures plunging.

While 30% to 50% of the rock struck by the Chicxulub impactor was made up of evaporite deposits like salt and gypsum, almost none of that material is found in the core. That provides more support for the idea that these minerals were vaporized, sending massive amounts of sulfur into the atmosphere where it could form sunlight-blocking particles. Much of the rest of the bedrock was limestone, which would have released CO2, causing the long-term global warming that followed after the short-lived sulfur particles washed out of the atmosphere.

In a world where a centimeter of sediment can take centuries to accumulate, the fact that 130 meters of material was deposited in a day is remarkable. More importantly, it gives you no shortage of clues to look through to learn about one of the wildest events in the geologic record—and the first day of the Cenozoic era.

PNAS, 2019. DOI: 10.1073/pnas.1909479116 (About DOIs).

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Google Maps gets new icon, tweaked UI for 15th birthday 0 11

Google Maps gets new icon, tweaked UI for 15th birthday

OK, but what about dark mode? —

There’s a new icon, new tabs, and the death of the hamburger button.


  • Left: the new Google Maps logo. Right: the old logo.

  • The new logo loosely follows Google’s new icon style, which is slowly creeping across the app lineup.

  • Here’s the “new” Google Maps. There are two new tabs at the bottom and “For You” was renamed to “Updates.” Also the hamburger button is dead.

  • Here are the two new tabs. Neither of these sections are new; they’re just tab buttons now.

Google Maps is turning 15 this year, and Google is celebrating with a new icon and a few UI tweaks.

First, the Google Maps icon is no longer, well, a map and is now a multi-colored map pin. Like all of Google’s other recent icons, Maps’ icon follows a formula of outfitting a simple shape or letter with the colors red, blue, green, and yellow, and calling it a day. You can expect this new icon to pop up on your phone sometime soon.

The bottom tab navigation is going to switch from three tabs to five, with new tabs for “Saved” (Saved places), “Contribute,” and “Updates.” None of these sections really represent new features, they just used to live in the left-side navigation drawer and now they have top-level access via the tab bar. Speaking of the left-side navigation drawer, the hamburger button that used to open it is dead. Presumably, the settings and other miscellaneous menu options will live under the account switcher, accessible via your profile picture on the right side of the search bar.

Crowdsourcing has always been a major source of information for Google Maps, and soon Google says it will start surfacing information based on surveys that past Google Maps users have filled out. Things like the temperature of a mass transit car, accessibility, and the security level will soon be surfaced when you’re planning your travels.

Google’s last update concerns the company’s augmented reality “Live View” mode in Maps. Instead of unreliable smartphone compass hardware, Live View cross-references your camera feed with Street View imagery to figure out the direction you’re facing. The feature is meant to help with walking navigation in big cities, where getting that first turn right can often be a challenge. Live View works, but location compatibility is currently extremely limited right now. Google says it will be “expanding Live View and testing new capabilities” over the coming months but doesn’t provide any detail on what, exactly, that means.

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Downloading public court documents costs a dime a page—is that legal? 0 18

Downloading public court documents costs a dime a page—is that legal?

Tear down this wall? —

Federal courts use hefty PACER fees to pay for non-PACER projects.


Chief Justice John Roberts.

Enlarge / Chief Justice John Roberts did not actually use PACER fees to buy a new chair. That’s just a hypothetical example.

Mark Wilson/Getty Images

If you need documents from federal court cases, you’re in luck. Almost every brief, exhibit, and legal ruling is available for download from the judiciary’s PACER website. But there’s a catch: documents cost 10 cents a page.

In 2016, three nonprofit organizations, the National Veterans Legal Services Program, the National Consumer Law Center, and the Alliance for Justice sued the federal courts—in federal court. The class action lawsuit, filed on behalf of all fee-paying PACER users, argued that these hefty charges were illegal. Federal law allows the courts to charge fees “only to the extent necessary” to provide public access to information. Over the last 15 years, the cost of storage and bandwidth has plunged. Yet PACER’s fees have actually risen from 7 cents to 10 cents. These fees have raised far more money than it costs to run the PACER system: $146 million in 2016 alone.

In a 2018 ruling, Judge Ellen Huvelle largely agreed with the plaintiffs, concluding that the courts are breaking the law by spending PACER money on non-PACER projects like installing flat-screen TVs in courtrooms and sending electronic notifications to bankruptcy creditors. On Monday, the case reached the Court of Appeals for the Federal Circuit, where three judges heard oral arguments from each side. Judges seemed skeptical of the arguments of government lawyers representing the judiciary.

Before I explain the arguments, I should note that I’m not a neutral observer on this issue. As a reporter, I’m a frequent user of PACER; Ars Technica will probably get some money back if the plaintiffs win this lawsuit. Also, a decade ago, I helped create RECAP, a browser extension that helps PACER users share documents with each other and avoid paying PACER fees. I’ve long been on record arguing that public court documents should be free to the public—not locked behind a paywall.

The current lawsuit wouldn’t go that far. Both sides agree that the courts are allowed to charge something for judicial documents. But the two sides in Monday’s oral arguments disagreed radically about how much the documents should cost. Plaintiffs argued that the law only allows the courts to charge the marginal cost of distributing documents—a tiny fraction of the current fee. The Administrative Office of the Courts, on the other hand, has argued for an expansive interpretation of the law that allows them to charge as much as they want and to spend it on anything related to distributing information electronically to the public.

In her 2018 ruling, Judge Huvelle charted a middle course. She ruled that the courts could not only charge for the cost of delivering a particular document to a particular customer, but also for the costs of maintaining the infrastructure behind the PACER system. That includes CM/ECF, the website that litigants and judges use to upload, organize, and view case documents. She concluded that these costs are relevant because PACER is fundamentally a public-facing front-end for the CM/ECF system. But she held that the courts couldn’t use PACER fees to pay for projects completely unrelated to PACER.

“We’re redecorating all judges’ offices with gold plate”

Monday’s oral arguments (MP3 recording here) didn’t go well for Alisa Klein, the government lawyer representing the judiciary. At one point an exchange got so testy that Judge Raymond Clevenger snapped, “Do you have a lot of trouble answering questions generally in life or just when you come in front of the court?”

Rather than directly defending the courts’ use of PACER fees for non-PACER purposes, Klein spent most of her time arguing that the courts shouldn’t be hearing the case at all—an issue known as “standing” in legal jargon. While the law restricts how fees can be spent, she said, Congress didn’t intend to let individual PACER users sue the courts if the law wasn’t followed.

The judges seemed skeptical. Clevenger asked incredulously whether it would be legal for PACER fees to be used to replace “the curtains at the Supreme Court” and to buy “the Chief Justice’s new chair.”

“We’re redecorating all judges’ offices with gold plate,” he said sarcastically. Under the judiciary’s theory, he said, “there’s absolutely no remedy” for this kind of illegal spending.

But Klein pointed out that the judiciary’s budget gets reviewed and approved every year by Congress. If Congress doesn’t want the courts spending PACER fees on gold-plated office renovations, Congress can easily nix expenses it doesn’t like. This annual process of oversight and appropriations, not lawsuits from private citizens, should shape spending decisions by the courts, she argued.

If the judges do decide that the courts have overcharged customers, they’ll be left with the tricky problem of deciding how much was overcharged. Deepak Gupta, the lawyer who represented the non-profit plaintiffs, said he didn’t have enough information to draw a clear line between permitted and illegal uses. He suggested that the judges send the case back down to the lower courts with instructions to dig into the courts’ budgets, uncover more information, and then rule on the issue.

While this lawsuit might force the courts to reduce PACER fees, eliminating the paywall entirely will probably take action from Congress. Last year, Rep. Doug Collins (R-Ga.) introduced legislation requiring the courts to make PACER documents available free of charge. But so far the bill hasn’t gotten much traction.

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