False mirror

A particle accelerator that slams electrons together here on Earth has achieved temperatures colder than those of outer space.

Using the X-ray free-electron laser at the Department of Energy's SLAC National Accelerator Laboratory – part of an upgrade project to the Linac Coherent Light Source (LCLS), called LCLS II – scientists chilled liquid helium to minus 456 degrees Fahrenheit (minus 271 degrees Celsius), or 2 kelvins.

That is just 2 kelvins above absolute zero, the coldest possible temperature at which all particle movement ceases.

That frosty environment is crucial for the accelerator, because at such low temperatures the machine becomes superconducting, meaning it can boost electrons through it with just about zero energy loss.

Even empty regions of space aren't this cold, as they are still filled with the cosmic microwave background radiation, a remnant from shortly after the Big Bang that has a uniform temperature of minus 454 F (minus 271 C), or 3 K.

"The next-generation superconducting accelerator of the LCLS-II X-ray free-electron laser has reached its operating temperature of 2 degrees above absolute zero," Andrew Burrill, director of the SLAC's Accelerator Directorate, told Live Science.

LCLS-II is now ready to begin accelerating electrons at 1 million pulses per second, which is a world record, he added.

"This is four orders of magnitude more pulses per second than its predecessor, LCLS, meaning that – in just a few hours – we will have sent more X-rays to users [who aim to utilize them in experiments] than LCLS has done in the past 10 years," Burrill said.

This is one of the last milestones that LCLS-II needs to achieve before it can go on to produce X-ray pulses that are on average 10,000 times brighter than those created by its predecessor.

This should help researchers to probe complex materials in unprecedented detail. The high-intensity, high-frequency laser pulses enable researchers to see how electrons and atoms in materials interact with unprecedented clarity.

This will have a number of applications, from helping to reveal "how natural and man-made molecular systems convert sunlight into fuels, and thus how to control these processes, to understanding the fundamental properties of materials that will enable quantum computing," Burill said.

As far as we know, it's not possible for a person to move at twice the speed of light. In fact, it's not possible for any object with the kind of mass you or I have to move faster than the speed of light.

However, for certain strange particles, traveling at twice the speed of light might be possible – and it might send those particles back in time.
A universal speed limit

One of our best physical theories at the moment is the theory of relativity, developed by Albert Einstein. According to this theory, the speed of light operates as a universal speed limit on anything with mass.

Specifically, relativity tells us that nothing with mass can accelerate past the speed of light.

To accelerate an object with mass, we have to add energy. The faster we want the object to go, the more energy we'll need.

The equations of relativity tell us that anything with mass – regardless of how much mass it has – would require an infinite amount of energy to be accelerated to the speed of light.

But all of the sources of energy we know of are finite: they are limited in some respect.

Indeed, it's plausible the Universe only contains a finite amount of energy. That would mean there isn't enough energy in the Universe to accelerate something with mass up to the speed of light.

Since you and I have mass, don't expect to be traveling at twice the speed of light anytime soon.
Tachyons

This universal speed limit applies to anything with what we might call "ordinary mass".

There are, however, hypothetical particles called tachyons with a special kind of mass called "imaginary mass".

There is no evidence tachyons exist. But according to relativity, their possible existence can't be ruled out.

If they do exist, tachyons must always be traveling faster than the speed of light. Just as something with ordinary mass can't be accelerated past the speed of light, tachyons can't be slowed down to below the speed of light.

Some physicists believe that if tachyons exist, they would constantly be traveling backwards in time. This is why tachyons are associated with time travel in many science fiction books and movies.

There are ideas that we might someday harness tachyons to build a time machine. But for now this remains a distant dream, as we don't have the ability to detect potential tachyons.

Malaria-Carrying Mosquitos Are Expanding Their Territory Almost 3 Miles a Year
Scientists have long warned that climate change would push species into new territories, with the march of disease-carrying mosquitos among their gravest concerns.

But this is not some theoretical future threat. Mosquitos that transmit malaria have been moving into warming areas for over a century in Africa, according to a new study.

Georgetown University biologist Colin Carlson and colleagues used one of the most comprehensive datasets ever compiled by medical entomologists to track the outer reaches of mosquito distribution in Africa over 120 years.

The data allowed the researchers to estimate the range limits of 22 species of Anopheles mosquitos between 1898 and 2016. In that time, the world has warmed by at least 1.2 degrees Celsius, opening new areas suitable to mosquitos.

As a result, Anopheles mosquitos have spread southward by 4.7 kilometers (nearly 3 miles) every year, and risen 6.5 meters in elevation each year.

That's further and faster than estimates from a 2011 study which reported that across the board, terrestrial species were moving poleward by 1.7 kilometers a year and upslope by 1.1 meters each year – a rate that was, at that time, roughly two to three times faster than previously thought.

In fact, this new study suggests that African Anopheles mosquitos have moved so far that, on average, they are now found 500 kilometers (310 miles) closer to the south pole and 700 meters (2,300 feet) farther uphill than they were at the turn of the 20th century.

The Origins of Binary Black Holes May Be Hidden in Their Spins, Study Suggests
In a recent study published in Astronomy and Astrophysical Letters, a team of researchers at the Massachusetts Institute of Technology (MIT) used various computer models to examine 69 confirmed binary black holes to help determine their origin and found their data results changed based on the model's configurations.

Essentially, the input consistently altered the output, and the researchers wish to better understand both how and why this occurs and what steps can be taken to have more consistent results.

"When you change the model and make it more flexible or make different assumptions, you get a different answer about how black holes formed in the universe," Sylvia Biscoveanu, an MIT graduate student working in the LIGO Laboratory, and a co-author on the study, said in a statement.

"We show that people need to be careful because we are not yet at the stage with our data where we can believe what the model tells us."

Like binary stars, binary black holes are two massive objects orbiting each other, with both having the ability to potentially collide – or merge – together, with another shared characteristic being black holes are sometimes born from the collapse of dying massive stars, also known as a supernova.

But how binary black holes originated remains a mystery, as there are two current hypotheses regarding their formation: "field binary evolution" and "dynamical assembly".

Field binary evolution involves when a pair of binary stars explode, resulting in two black holes in their place, which continue orbiting each other the same as before.

We've Just Seen an 'Exceptional' Once-in-a-Millennium Space Explosion
A record-breaking gamma-ray burst detected in October 2022 has now been described as a one-in-a-thousand years event.

It's called GRB 221009A, and with up to 18 teraelectronvolts of energy packed in its emissions of light, it's considered the most powerful gamma-ray burst on record.

We've been waiting to learn more about this incredible explosion, and now the analyses have started to arrive on preprint server arXiv, with a trio of papers submitted to The Astrophysical Journal Letters.

According to the analyses, this exceptional burst of light is breaking rules: the light curve of its afterglow doesn't neatly adhere to theoretical descriptions of how it should go, suggesting that there's something interesting and unique about GRB 221009A.

To recap, gamma-ray bursts are the most violent explosions in the Universe, erupting in fire and fury so powerful they release more energy than the Sun would in 10 billion years. The outbursts of electromagnetic radiation are caused by cataclysmic events: the supernova or hypernova explosions massive stars undergo at the end of their lifetimes, or collisions of binary systems involving at least one neutron star.

Now That They've Actually Looked, Scientists Discover Snakes Have Two Clitorises
It's been a big year for the cl****is.

In January, scientists discovered bottlenose dolphins have a large S-shaped cl****is that might be better placed for pleasure than our own species' version.

And just last month, researchers realized they had once again underestimated the female s*x organ, when a study showed more than ten thousand nerve endings innervate the human female erogenous organ.

Now, for the first time, scientists have uncovered the equivalent s*x organ in female snakes, striking down a host of misconceptions in the process.

Reproductive biologist Megan Folwell of the University of Adelaide in Australia and colleagues peeled back the layers of female snake genitalia across nine different species, using micro-CT imaging and dissection techniques.

They found that like their male counterparts who have two pen*ses (called hemipenes), female snakes have two hemiclitores that form a triangular structure that varies in size and shape.

"It was such a prominent structure that was completely different to the hemipenes and clearly different to the scent glands and surrounding tissue," Folwell tells ScienceAlert. "The variation across species and the presence of nerve fibers was amazing!"