By the second trimester, long before a baby's eyes can see images, they can detect light.

But the light-sensitive cells in the developing retina — the thin sheet of brain-like tissue at the back of the eye — were thought to be simple on-off switches, presumably there to set up the 24-hour, day-night rhythms parents hope their baby will follow.

University of California, Berkeley, scientists have now found evidence that these simple cells actually talk to one another as part of an interconnected network that gives the retina more light sensitivity than once thought, and that may enhance the influence of light on behavior and brain development in unsuspected ways.

In the developing eye, perhaps 3% of ganglion cells — the cells in the retina that send messages through the optic nerve into the brain — are sensitive to light and, to date, researchers have found about six different subtypes that communicate with various places in the brain. Some talk to the suprachiasmatic nucleus to tune our internal clock to the day-night cycle. Others send signals to the area that makes our pupils constrict in bright light.

But others connect with surprising areas: the perihabenula, which regulates mood, and the amygdala, which deals with emotions.

In mice and monkeys, recent evidence suggests that these ganglion cells also talk with one another through electrical connections called gap junctions, implying much more complexity in immature rodent and primate eyes than imagined.

"Given the variety of these ganglion cells and that they project to many different parts of the brain, it makes me wonder whether they play a role in how the retina connects up to the brain," said Marla Feller, a UC Berkeley professor of molecular and cell biology and senior author of a paper that appeared this month in the journal Current Biology. "Maybe not for visual circuits, but for non-vision behaviors. Not only the pupillary light reflex and circadian rhythms, but possibly explaining problems like light-induced migraines, or why light therapy works for depression."

Even though the creature's remains were well-preserved due to freezing temperatures, scientists are yet to determine what kind of canine it actually was.

The remains of an ancient puppy found buried in permafrost in the vicinity of the Indigirka River in Siberia, north-east of Yakutsk, left researchers scratching their heads as even a DNA test didn't help them determine the exact nature of the creature, The Siberian Times reports.

According to the media outlet, the puppy was originally discovered in 2018, with all of its body intact, including whiskers and eyelashes.

But while scientists were able to establish that the creature lived about 18,000 years ago and that it was about two-months old at the time of its death, the initial genome sequencing performed by Swedish Centre for Palaeogenetics (CPG) failed to define whether the creature was a wolf or a dog.

Humans can't fly, but we're determined to work out how others do.

Last month a Canadian team suggested that the way birds move their wings, rather than the shape of those wings, determines how they fly.

Now researchers from Stanford University, US, have watched five parrotlets in flight and discovered that - counterintuitive as it might sound - they used drag to help with their take-off and lift to assist with landing.

Conventional wisdom tells us that drag is a force that slows an object down and lift is a force that counters gravity. However, in this case drag supported up to half of the birds' (admittedly low) body weight at a crucial time, while lift helped with braking.

David Lentink and Diana Chin made the finding after encouraging Gaga, Gary, Oreo, Aurora and Boy to make repeated flights from perch to perch through an instrumented flight chamber developed specifically for the purpose.

It was only 80 centimetres long, but then the birds only weigh 30 grams - and a grain of millet was sufficient inducement for each trip.

To measure the horizontal and vertical forces instantaneously, Chin built a setup with sensor panels on the floor, ceiling, front and back of the birds' flight paths.

For most people, continents are Earth's seven main large landmasses.

But geoscientists have a different take on this. They look at the type of rock a feature is made of, rather than how much of its surface is above sea level.

In the past few years, we've seen an increase in the discovery of lost continents. Most of these have been plateaus or mountains made of continental crust hidden from our view, below sea level.

One example is Zealandia, the world's eighth continent that extends underwater from New Zealand.

Several smaller lost continents, called microcontinents, have also recently been discovered submerged in the eastern and western Indian Ocean.

Seventy years ago, science fiction writer Isaac Asimov imagined a world where robots would serve humans in countless ways, and he equipped them with built-in safeguards - now known as Asimov's Three Laws of Robotics, to prevent them, among other goals, from ever harming a person.

Guaranteeing safe and fair machine behavior is still an issue today, says machine learning researcher and lead author Philip Thomas at the University of Massachusetts Amherst. "When someone applies a machine learning algorithm, it's hard to control its behavior," he points out. This risks undesirable outcomes from algorithms that direct everything from self-driving vehicles to insulin pumps to criminal sentencing, say he and co-authors.

One of the biggest, and most consequential, debates in science is the question of whether the universe, and the life it harbors, are intelligently designed, or whether we all exist only by random chance. Many minds far greater than mine have debated the matter pro and con for years. I have the audacity to propose a simple theorem that will put the matter to rest. Here it is:

Randomness can operate only within nonrandom parameters.

The truth of that utterance is manifold, and its implications are all-embracing. Acceptance or rejection of that simple statement decides whether we, as a society, accept moral principles that cannot possibly come from the human mind, but only from the Supreme Being.

Although this very brief commentary cannot encompass all the complexities, let us nevertheless begin with the manifold layers of proof, and then proceed to the implications.

To start us off, here is a trick question, using a pair of dice as the example. Rolling a single die from the pair, what are the chances of the die-roll "landing a six?" If you answered, one chance in six, then you fell for the trick. I never said that the die being rolled has six sides. Dice can have any number of sides, from four upward.

When you hear the word "cyborg," scenes from the 1980s films RoboCop or The Terminator might spring to mind. But the futuristic characters made famous in those films may no longer be mere science fiction. We are at the advent of an era where digital technology and artificial intelligence are moving more deeply into our human biological sphere. Humans are already able to control a robotic arm with their minds. Cyborgs — humans whose skills and abilities exceed those of others because of electrical or mechanical elements built into the body — are already among us.

But innovators are pushing the human-machine boundary even further. While prosthetic limbs are tied in with a person's nervous system, future blends of biology and technology may be seen in computers that are wired into our brains.

Our ability to technologically enhance our physical capabilities — the "hardware" of our human systems, you could say — will likely reshape our social world. Will these changes bring new forms of dominance and exploitation? Will unaltered humans be subjected to a permanent underclass or left behind altogether? And what will it mean to be human — or will some of us be more than human?

Initial answers may be closer than we think.

Physicist Max Tegmark, MIT professor and president of the Future of Life Institute, considers the recent advances in artificial intelligence and technology through an evolutionary lens to imagine us as "more than human." He categorizes all life into three levels. In his view, the vast majority of life — from bacteria to mice, iguanas to lobsters — falls into what he calls Life 1.0. These creatures survive and replicate, but they cannot redesign themselves within their lifetime. They evolve and "learn" over many generations.

In some ways, the most Earth-like world in our solar system (other than Earth, obviously) is Saturn's largest moon, Titan. And now, astronomers from NASA JPL and Arizona State University have used years of Cassini data to construct the first global map of Titan.

From space, Titan just looks like a featureless, orange-brown moon - but that's because of its thick atmosphere. The Cassini mission peered through the hazy clouds and revealed a fascinating surface of complex geology, carved from a hydrologic cycle much like Earth's. Titan is the only place besides our homeworld that's known to have lakes, rivers, oceans and rains - but rather than water, it's liquid methane and ethane.

"Titan has an active methane-based hydrologic cycle that has shaped a complex geologic landscape, making its surface one of most geologically diverse in the solar system," says Rosaly Lopes, lead author of the new research. "Despite the different materials, temperatures and gravity fields between Earth and Titan, many surface features are similar between the two worlds and can be interpreted as being products of the same geologic processes."

Far beneath the Hindu Kush mountains of Central Asia, a giant blob of continental rock is slowly dripping away from the lithosphere into the mantle below. A recent study attributed many of the deepest earthquakes in the region to the movements of this blob.

The Hindu Kush runs for hundreds of miles and straddles the border of Afghanistan and Pakistan. It is one of the most seismically active areas in the world.

Every year, the mountain range gets rocked by more than 100 earthquakes that measure a magnitude of 4.0 or higher. It also experiences many intermediate-depth quakes that happen between 45 to 190 miles (70 to 300 kilometers) below the surface.

Until recently, experts didn't know why the Hindu Kush suffers so many earthquakes at intermediate depths. The mountain range doesn't sit on top of a significant fault line, which any California resident knows causes numerous earthquakes.

Further, the mountains are some distance away from the ongoing collision between the Eurasian and Indian tectonic plates. Therefore, the usual candidates for the cause behind constant earthquakes are absent from the area. (Related: Fracking-induced earthquakes in Central and Eastern America are on the rise, caution researchers.)

A new paper suggests that the mysterious X17 subatomic particle is indicative of a fifth force of nature.
Physicists have long known of four fundamental forces of nature: gravity, electromagnetism, the strong nuclear force, and the weak nuclear force.

Now, they might have evidence of a fifth force.

The discovery of a fifth force of nature could help explain the mystery of dark matter, which is proposed to make up around 85 percent of the universe's mass. It could also pave the way for a unified fifth force theory, one that joins together electromagnetic, strong and weak nuclear forces as "manifestations of one grander, more fundamental force," as theoretical physicist Jonathan Feng put it in 2016.

The new findings build upon a study published in 2016 that offered the first hint of a fifth force.

In 2015, a team of physicists at Hungary's Institute for Nuclear Research was looking for "dark photons," which are hypothetical particles believed to "carry" dark matter. To catch a glimpse of these strange forces at work, the team used a particle accelerator to shoot particles through a vacuum tube at high speeds. The goal was to observe the way isotopes decay after thrust into high-energy states — anomalies in the way particles behave could suggest the presence of unknown forces.

So, the team closely watched the radioactive decay of beryllium-8, an unstable isotope. When the particles from beryllium-8 decayed, the team observed unexpected light emissions: The electrons and positrons from the unstable isotope tended to burst away from each other at exactly 140 degrees. This shouldn't have happened, according to the law of conservation of energy. The results suggested that an unknown particle was created in the decay.