Adi Foord, University of Maryland, Baltimore County

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to [email protected].

Will it ever be possible for time travel to occur? – Alana C., age 12, Queens, New York

Have you ever dreamed of traveling through time, like characters do in science fiction movies? For centuries, the concept of time travel has captivated people’s imaginations. Time travel is the concept of moving between different points in time, just like you move between different places. In movies, you might have seen characters using special machines, magical devices or even hopping into a futuristic car to travel backward or forward in time.

But is this just a fun idea for movies, or could it really happen?

The question of whether time is reversible remains one of the biggest unresolved questions in science. If the universe follows the laws of thermodynamics, it may not be possible. The second law of thermodynamics states that things in the universe can either remain the same or become more disordered over time.

It’s a bit like saying you can’t unscramble eggs once they’ve been cooked. According to this law, the universe can never go back exactly to how it was before. Time can only go forward, like a one-way street.

Time is relative

However, physicist Albert Einstein’s theory of special relativity suggests that time passes at different rates for different people. Someone speeding along on a spaceship moving close to the speed of light – 671 million miles per hour! – will experience time slower than a person on Earth.

People have yet to build spaceships that can move at speeds anywhere near as fast as light, but astronauts who visit the International Space Station orbit around the Earth at speeds close to 17,500 mph. Astronaut Scott Kelly has spent 520 days at the International Space Station, and as a result has aged a little more slowly than his twin brother – and fellow astronaut – Mark Kelly. Scott used to be 6 minutes younger than his twin brother. Now, because Scott was traveling so much faster than Mark and for so many days, he is 6 minutes and 5 milliseconds younger.

Some scientists are exploring other ideas that could theoretically allow time travel. One concept involves wormholes, or hypothetical tunnels in space that could create shortcuts for journeys across the universe. If someone could build a wormhole and then figure out a way to move one end at close to the speed of light – like the hypothetical spaceship mentioned above – the moving end would age more slowly than the stationary end. Someone who entered the moving end and exited the wormhole through the stationary end would come out in their past.

However, wormholes remain theoretical: Scientists have yet to spot one. It also looks like it would be incredibly challenging to send humans through a wormhole space tunnel.

Paradoxes and failed dinner parties

There are also paradoxes associated with time travel. The famous “grandfather paradox” is a hypothetical problem that could arise if someone traveled back in time and accidentally prevented their grandparents from meeting. This would create a paradox where you were never born, which raises the question: How could you have traveled back in time in the first place? It’s a mind-boggling puzzle that adds to the mystery of time travel.

Famously, physicist Stephen Hawking tested the possibility of time travel by throwing a dinner party where invitations noting the date, time and coordinates were not sent out until after it had happened. His hope was that his invitation would be read by someone living in the future, who had capabilities to travel back in time. But no one showed up.

As he pointed out: “The best evidence we have that time travel is not possible, and never will be, is that we have not been invaded by hordes of tourists from the future.”

Telescopes are time machines

Interestingly, astrophysicists armed with powerful telescopes possess a unique form of time travel. As they peer into the vast expanse of the cosmos, they gaze into the past universe. Light from all galaxies and stars takes time to travel, and these beams of light carry information from the distant past. When astrophysicists observe a star or a galaxy through a telescope, they are not seeing it as it is in the present, but as it existed when the light began its journey to Earth millions to billions of years ago.

NASA’s newest space telescope, the James Webb Space Telescope, is peering at galaxies that were formed at the very beginning of the Big Bang, about 13.7 billion years ago.

While we aren’t likely to have time machines like the ones in movies anytime soon, scientists are actively researching and exploring new ideas. But for now, we’ll have to enjoy the idea of time travel in our favorite books, movies and dreams.

Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to [email protected]. Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.

Adi Foord, Assistant Professor of Astronomy and Astrophysics, University of Maryland, Baltimore County

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bill Sullivan, Indiana University

More than 37 million people in the U.S. have diabetes. According to the American Diabetes Association, 8.4 million Americans needed to take insulin in 2022 to lower their blood sugar. Insulin, however, is tricky to deliver into the body orally because it is a protein easily destroyed in the stomach.

While researchers are developing pills that resist digestion in the stomach and skin patches that monitor blood sugar and automatically release insulin, the most reliable way currently to take insulin is through frequent injections.

I am a professor of pharmacology and toxicology at Indiana University School of Medicine, where my colleagues and I study drug delivery systems. Researching innovative new ways to get medications into the body can improve how well patients respond to and comply with treatments. An easier way to take insulin would be music to the ears of many people with diabetes, especially those who aren’t fans of needles.

In a recent study in The Lancet Diabetes & Endocrinology, researchers engineered cells to release insulin in response to specific sound waves: the music of the band Queen. Though it still has a long way to go, this new system may one day replace the insulin injection with a dose of rock ’n’ roll.

What is diabetes?

Diabetes is a chronic disease that arises when the body fails to make enough insulin or respond to insulin. Insulin is a hormone the pancreas makes in response to the rise in sugar concentration in the blood when the body digests food. This crucial hormone gets those sugars out of the blood and into muscles and tissues where it is used or stored for energy.

Without insulin, blood sugar levels remain high and cause symptoms that include frequent urination, thirst, blurry vision and fatigue. Left untreated, this hyperglycemia can be life-threatening, causing organ damage and a diabetic coma. According to the U.S. Centers for Disease Control and Prevention, diabetes is the No. 1 cause of kidney failure, lower-limb amputations and adult blindness, making it the eighth most common cause of death in the U.S.

Treating diabetes is straightforward: When the body is lacking insulin, give it more insulin. Scientists have mastered how to make the hormone, but direct injection is the only effective way to get it into the body. Diabetic patients usually have to carry insulin vials and needles wherever they go. Considering that many people fear needles, this may not be an ideal way to manage the disease.

This challenge has sparked researchers to look into new ways to deliver insulin more easily.

What is cellular engineering?

Cells are the basic unit of life. Your body is composed of hundreds of different types of cells that carry out specialized functions. In some diabetic patients, the pancreatic beta cells that make insulin have malfunctioned or died. What if there were a way to replace these defective cells with new ones that could produce insulin on demand?

That’s where cellular engineering comes in. Cellular engineering involves genetically modifying a cell to perform a specific function, like producing insulin. Installing the gene that makes insulin into cells is not difficult, but controlling when the cell makes it has been a challenge. Insulin should be made only in response to high blood sugar levels following a meal, not at any other time.

Scientists have been exploring the idea of using ion channels – proteins embedded in a cell’s membrane that regulate the flow of ions such as calcium or chloride – like a remote-controlled device to activate cellular activity. Cells with specific types of ion channel in their membranes can be activated in response to certain stimuli, such as light, electricity, magnetic fields or mechanical stimulation. Such ion channels exist naturally as sensory devices to help cells and organisms respond to light, magnetism, touch or sound. For example, hair cells in the inner ear have mechanosensitive ion channels that respond to sound waves.

Combining cellular engineering with Queen

Bioengineering professor Martin Fussenegger of ETH Zurich, a university in Basel, Switzerland, led a recent study that used a mechanosensitive ion channel as a remote control to signal cells to make insulin in response to specific sound waves.

These “MUSIC-controlled, insulin-releasing cells” – MUSIC is short for music-inducible cellular control – were cultured in the lab next to loudspeakers. His team tested a variety of musical genres of different intensities and speeds.

Among the songs they played were pop songs like Michael Jackson’s “Billie Jean,” Queen’s “We Will Rock You” and the Eagles’ “Hotel California”; classical pieces such as Beethoven’s “Für Elise” and Mozart’s “Alla Turca”; and movie themes such as Soundgarden’s “Live To Rise,” which was featured in “The Avengers,” a Marvel film. They found that pop music heavy in low bass and movie soundtracks were better able to trigger insulin release compared with classical music, and cells were able to release insulin within minutes of exposure to the song.

In particular, they found that the Queen song “We Will Rock You” most faithfully mimicked the rate of insulin release in normal pancreatic beta cells.

The team then implanted the MUSIC-controlled, insulin-releasing cells into diabetic mice. Listening to the Queen song for 15 minutes once a day returned the amount of insulin in their blood to normal levels. Blood sugar levels returned to normal as well. In contrast, mice that were not exposed to the song remained hyperglycemic.

Could music make insulin in people?

Despite these promising results, much more research is needed before this musical approach to producing insulin can be considered for human use.

One concern is the possibility of making too much insulin, which can also cause health problems. Fussenegger’s study found that talking and background noise such as the racket made by airplanes, lawn mowers or firetrucks did not trigger the insulin production system in mice. The music also needed to be played close to the abdomen where the MUSIC-controlled, insulin-releasing cells were implanted.

In an email, Fussenegger explained that extensive clinical trials must be performed to ensure efficacy and safety of the technique and to determine how long the cellular implants can last. As with introducing any foreign material into the body, tissue rejection is also a concern.

Cellular engineering may one day provide a much-needed alternative to frequent injections of insulin for the millions of people with diabetes around the world. In the future, different cell types could be engineered to release other drugs in the body more conveniently.

Bill Sullivan, Professor of Pharmacology & Toxicology, Indiana University

This article is republished from The Conversation under a Creative Commons license. Read the original article.