## Dangerous ‘naked’ black holes could be hiding in the universe

Black holes are regions of infinite density, known as a singularity. And according to mainstream physics, each of these cosmic matter munchers is fringed by an event horizon –- a boundary where once you fall in, you never come out.

An illustration of a black hole.

But what if some black holes are naked — completely lacking such frontiers? As far as we can tell, singularities are always wrapped in event horizons, but a more detailed look at the math of general relativity suggests that doesn’t have to be the case.

If such naked black holes dot the universe, new research reveals how we might be able to detect one: by looking at the ring of light surrounding it.

Related: What’s inside a black hole?

## ‘The Emperor Has No Clothes’

Black holes are a consequence of the mathematics of Einstein’s theory of general relativity. Those equations tell us that if a clump of matter collapses on itself into too small of a volume, the gravity of that matter will just keep shrinking it ever smaller until it crushes into an infinitely tiny point. That point is called a singularity, and it’s a signal that the math we’re using to describe spacetime is completely breaking down.

The gravitational pull of a singularity is infinitely strong. Objects can be pulled toward the singularity faster than the speed of light. Near a singularity, the physics of general relativity can no longer predict the future trajectory of particles — which is one of the main points of physics. Without the power to make predictions, physics falls apart.

Related: 8 ways you can see Einstein’s theory of relativity in real life

Thankfully, as far as we know, all singularities are wrapped in an event horizon. The event horizon is the distance away from the singularity where the gravitational attraction is strong enough to pull in anything –- the point where you would have to travel faster than the speed of light to escape. That’s what makes a black hole black — even light can’t escape them.

Ever since we first discovered the existence of black holes, we’ve wondered if it’s possible to form a singularity without the associated event horizon — a so-called “naked” singularity. This would be a very dangerous place indeed, because it would be a location where the laws of physics break down that is fully accessible to the rest of the universe. At least with a traditional black hole, the singularity is safely wrapped beneath an event horizon, so even though it’s a place of extreme and unknown physics, at least whatever happens there is locked away from the rest of the cosmos.

## Twisting a point

If naked singularities exist, they certainly aren’t common. We know of only one confirmed way of forming singularities, and that’s when a giant star runs out of fuel and collapses in on itself. When that happens, the singularity naturally gets an event horizon.

The presence of a naked singularity

## How Hackers Could Trick Unwitting Scientists Into Producing Dangerous Genes

In a new letter to the editor pulled from the prestigious scientific journal Nature, a team of Israeli researchers pose a frankly wild-sounding question: could a computer hack result in a scientist being swindled into creating a piece of genetic code that’s harmful—or potentially toxic—rather than helpful?

The answer seems to be yes, albeit with some pretty weighty caveats. The “end-to-end cyberbiological attack” described above requires some lackluster cybersecurity chops from both sides of the genetic research supply chain: both the academics who might order genetic materials online, and the labs that might supply those materials back. While this sort of attack hasn’t been seen in the wild yet, the research team behind the letter pointed out that it’s not outside the realm of possibility—especially as more and more genetic research moves into the digital realm.

At the heart of this hypothetical hack is the software that biologists use to “print” strands of DNA from scratch and then assemble them together, a process known as “DNA synthesis.” In recent years, we’ve seen this synthesizing software underpin tons of groundbreaking biomedical research. In the mad dash to create a treatment for Covid-19, for instance, a handful of major pharma companies turned to using man-made strands of DNA as one of the components of their experimental vaccines.

But software—even software that’s used to write strings of biological code—is still software, which means it can still be hacked. Futurists and scientists alike have been sounding that specific alarm for years. And back in 2017, a team of researchers from the University of Washington even demonstrated that it was possible to encode malware directly into one of these synthetic DNA strands, albeit with a lot of trial and error, and the malware only worked because they intentionally borked the software they intended to attack. (And, as Wired wrote though, “the attack was fully translated only about 37 percent of the time.”)

Both that case and the case described in this new letter are theoretical. But as the Israeli researchers put it, of these cases are theoretical. But as the Israeli team puts it, “the threat is real”—especially as synthetic DNA underlies more and more biomedical research.

Here’s how the hack would (theoretically) go down: let’s say you have a bioengineer working out of a University, who happens to be working on a new vaccine that requires specific strings of synthetic DNA. These strings are each constructed of four different chemical building blocks—or “bases,” in biology parlance—arranged in a specific sequence.

As the researchers point out, not every academic institution has the greatest cybersecurity chops, which means it’s entirely possible for a bad actor to hijack this engineer’s computer with some sort of malware. Because the bulk of buying these synthetic DNA strands happens online, there’s a chance that the bad actor

## Carter Estes: Effort to ban Trump officials from Harvard is a dangerous attack on free speech and education

My fi

My first year at the Harvard Kennedy School of Government hasn’t been what I expected — and I’m not just talking about all the restrictions to guard against the spread of COVID-19. I couldn’t have predicted that I’d be delivering a speech to my peers urging them to uphold free speech at one of America’s most prestigious centers of learning.

Unfortunately, I recently found myself on Zoom urging members of the Harvard Kennedy School Student Government to reject a student-led effort to restrict Trump administration officials from speaking at Harvard.

While I am relieved that the student government ultimately rejected the restrictions, I remain disturbed that my peers would propose this action and that it actually could have passed. An education underpinned by conditions of censorship is not a real education. And those who seek an education should never demand protection from ideas.

SOME HARVARD STUDENTS SAY NOT SO FAST ON TRUMP BAN

I came to Harvard to learn. But institutions of higher education that allow for restrictions on information and dialogue —whether imposed by students or administrators — forfeit the title of “educational institution” in exchange for the title “indoctrination center.” The latter is not what I signed up for. I want Harvard to deliver the education it claims to offer.

## More from Opinion

I am shocked and disappointed that some of my fellow graduate students — who surely came to one of the world’s top government affairs graduate programs to grow intellectually and professionally—would make these demands. The authors of the letter calling for banning Trump officials from campus said the reason for the ban was to, ironically, stop the “subversion of democratic principles” by the Trump administration. But free speech is a democratic principle.

The authors of this letter seek to cancel debate and silence political opposition. They are terrified of having their world views challenged. But that’s exactly why earnest minds have traditionally come to Harvard.

The Kennedy School has hosted many controversial figures, including members of the Clinton and Nixon administrations, former Obama Attorney General Eric Holder, and the late secretary-general of the Palestine Liberation Organization, Saeb Erekat.

We students are adults and we are fully capable of hearing uncomfortable and offensive information and arguments. It will only make us better.

I am a conservative. Harvard is an overwhelmingly liberal institution. I have only benefitted by having my ideas and values challenged while studying here. But more than that, Harvard owes it to students like me to be honest about what it claims to offer — a rigorous intellectual environment and access to top leaders.

Whether you agree with Trump policies or not, those who served in Trump administration have firsthand knowledge and experience in the highest levels of domestic and foreign policy. These players have impacted the world and we students can decide if their marks were good or bad, and conclude the missteps for ourselves.

But the onus is on universities to uphold their missions. They need to teach their students

## Carrying Children In Cargo Bikes Can Be Dangerous, New Report Finds

Cargo bikes are becoming more widely used by transportation and delivery companies. Some studies estimate that in years to come, with the variety of models coming on the market and sales growing rapidly, cargo bikes will be used for about 50% of the delivering of goods.

Families, too, have recognized the benefits of these increasingly popular modes of transport, but carrying children in them can be dangerous and are only safe if parents strap them in.

Those are the main findings of new research showing that children can safely ride on cargo bikes, but only when the bike is equipped with a seat belt system – and when this system is actually used. The results were released on Thursday by DEKRA, a company based in Germany that conducts automotive testing, inspection and crash research.

“When the dummy was strapped in, its position hardly changed when the brakes were applied,” Peter Rücker, Head of DEKRA Accident Research, said in a statement.. “In the test in which the dummy was not strapped in, however, the dummy was thrown out of the box and hit its head on the road. An accident like this would result in severe head injuries – especially without a helmet.”

The analysis was based on a series of tests conducted for the DEKRA Road Safety Report 2020, which examined two-wheeled modes of transportation from a variety of perspectives.  The annual report focuses on a different topic every year.

Testing for the cargo bike study was conducted at Dekra’s Technology Center in Brandenburg, Germany. Experts assessed and compared two scenarios: with a child dummy strapped in with the seat belt system offered by the manufacturer and placed on the seat in the cargo box and not strapped in. Braking was performed with the bicycle’s own brakes from a speed of 25 km/h.

This year’s report highlighted the benefits of cargo bikes to families. Unlike conventional child bicycle seats, it said, cargo bikes can accommodate two children, which makes it easier for parents, and they provide their young passengers with ample space to move around.

And compared to traveling in a trailer when they are in the parent’s field of vision, in cargo bikes, children can better enjoy the view around them.

But the report’s researchers also stressed the importance of safety and issued a series of recommendations:

• Whenever parents or other caretakers let children ride on a cargo bike, they must always make sure they are strapped in.
•  To offer protection in order to prevent head injuries during collisions with other road users, a helmet is “urgently recommended.”
• Bicycle retailers should always ask customers how they intend to use their cargo bikes. “The dealer should insist that the customer purchase a suitable model fitted with a seat belt system,” the report suggested, if they plan to transport children.

“The

## Wildfires can cause dangerous debris flows

Wildfires don’t stop being dangerous after the flames go out. Even one modest rainfall after a fire can cause a deadly landslide, according to new UC Riverside research.

“When fire moves through a watershed, it creates waxy seals that don’t allow water to penetrate the soil anymore,” explained environmental science doctoral student and study author James Guilinger.

Instead, the rainwater runs off the soil surface causing debris flows, which are fast-moving landslides that usually start on steep hills and accelerate as they move.

“The water doesn’t behave like water anymore, it’s more like wet cement,” Guilinger said. “It can pick up objects as big as boulders that can destroy infrastructure and hurt or even kill people, which is what happened after the 2018 Thomas fire in Montecito.”

Guilinger and his team of mentors and collaborators wanted to understand in detail how multiple storm cycles affect an area that’s been burned by wildfire, since Southern California tends to have much of its rain in the same season.

The team headed to the burn scar caused by the 23,000-acre Holy Fire near Lake Elsinore to observe this phenomenon, and their results have recently been published in the Journal of Geophysical Research: Earth Surface.

“It’s only recently that technology has advanced to the point that we can directly monitor soil erosion at extremely small scales,” said Andrew Gray, assistant professor of watershed hydrology and Guilinger’s advisor. Gray’s laboratory works to understand how wildfire impacts the movement of water and sediment through landscapes after wildfire.

Even with the latest technology, the data was not easy to obtain. To deploy their ground-based laser scanner, which uses visible and infrared waves to reconstruct surfaces down to millimeter accuracy, the scientists had to climb steep hill slopes. They also deployed drones in collaboration with Nicolas Barth, assistant professor of geomorphology, in order to zoom out and see up to 10 hectares of land after the storms.

What they found is that most of the soil in channels at the bottom of valleys between hill slopes eroded during the first few rains, even though the rains were relatively modest. The channels fill with material during the years between fires as well as in response to fire, with rain then causing rapid erosion resulting in the debris flows.

“This proves the first storm events that strike an area are the most critical,” Guilinger said. “You can’t really mitigate them at the source. Instead, people downstream need to be aware of the dangers, and land managers need hazard modeling tools to help them respond effectively and create a plan to catch the sediment as it flows.”

U.S. Geological Survey models incorporate widely available 10-meter data for watershed slopes and information about burn severity