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Astronomers have spotted an apparent supermassive black hole snacking on a star 600 million light-years away, wandering through a galaxy with an even larger black hole at its core.

The event, dubbed AT2024tvd, was first spotted by the Palomar Observatory’s Zwicky Transient Facility and later confirmed by powerhouse space telescopes including Hubble and Chandra, which helped zero in on the cosmic crime scene. To the researchers’ surprise, the responsible black hole was not at the center of its host galaxy, as supermassive black holes tend to be. Rather, this one was 2,600 light-years from the galactic center—a huge distance on paper, but really just one-tenth the distance between our Sun and Sagittarius A*, the black hole at the center of the Milky Way.

Tidal disruption events (TDEs) like this one occur when a black hole’s gravity pulls on a star so violently that the less massive ball of gas is stretched, shredded, and swirled around the black hole, in a process delightfully called spaghettification. The fleeting burst of energy from the event is gargantuan, even rivaling a supernova—the explosive death of a massive star—in brightness. The burst of light is also visible across the electromagnetic spectrum, making TDEs an invaluable resource for spotting black holes that might otherwise be too quiet or hidden to detect, such as the recent rogue object.

What makes AT2024tvd special is that it’s the first offset TDE discovered by optical surveys, according to a forthcoming paper in The Astrophysical Journal Letters, which is also posted on the preprint server arXiv. The achievement demonstrates how rogue black holes—warping spacetime and shrouded in darkness as they move through the cosmos—can be spotted, as long as an unfortunate object sacrifices itself for the massive object to reveal itself.

“Tidal disruption events hold great promise for illuminating the presence of massive black holes that we would otherwise not be able to detect,” said study co-author Ryan Chornock, a researcher at the University of California – Berkeley and a member of the ZTF team, in a NASA release. “Theorists have predicted that a population of massive black holes located away from the centers of galaxies must exist, but now we can use TDEs to find them.”

The team has a couple of ideas about how the rogue black hole ended up offset in the galaxy, and so close to the supermassive black hole at its core. (The rogue black hole’s mass is estimated to be roughly one million solar masses, at least ten times smaller than the black hole at the galactic center.) One option is that the black hole was at the center of a smaller galaxy that was subsumed by the larger galaxy, and now the black hole is simply drifting through the larger galaxy. Another possibility is that the black hole was the weakest link in what was once a three-body system, and was pushed out by the bigger objects; in other words, two larger black holes may lurk at the galaxy’s core, and the rogue black hole was ejected thousands of light-years out.

“If the black hole went through a triple interaction with two other black holes in the galaxy’s core, it can still remain bound to the galaxy, orbiting around the central region,“ said Yuhan Yao, also a researcher at UC Berkeley and the lead author of the study, in the same release. But at the present moment, the team isn’t sure if the black hole was pushed out or is being dragged in by the larger black hole.

With future instruments like the Vera Rubin Observatory and the Roman Space Telescope coming online, astronomers are hopeful this is just the beginning of an entirely new class of discoveries. Because if there’s anything more unsettling than a black hole swallowing a star, it’s the idea that the hungry, hungry objects are just drifting through space in unexpected locations.

One of science fiction’s favorite themes is time travel. HG Wells wrote The Time Machine back in 1895, but Gaspar wrote El Anacronópete in 1887, which also featured time travel. Charles Dickens hammered out A Christmas Carol in 1843, which also technically features a man traveling both to the past and future. Our fascination with the concept has endured ever since.

What makes time travel so appealing may be the fact that there are circumstances when science allows for the possibility of it happening, at least in theory. For instance, all of us are traveling into the future at this very moment. It happens nonstop at a speed of one second per second! 

But that’s not what most of us mean when we say time travel, is it? We’re talking about going back and riding a dinosaur, or traveling way into the future and riding a robot dinosaur. So, is that possible? Let’s take a look!

Time Dilation and Clocks

Dr. Ana Alonso-Serrano has explained how space and time are not absolute values. Mathematically, which is to say on paper, you can account for literally curving space and time around so that you make it into a loop, which is what time travel is. But the problem is translating things from paper to reality. Physically speaking, we need to understand more before any of this could ever become real. 

What we do understand, and can even demonstrate right now, is how time dilation works. The idea behind time dilation is that time actually passes differently for different observers, depending on several factors that affect it, including gravitational fields and relative motion. In very simple terms, as far as it can be most easily understood by us on the ground, speed and gravity affect time. All of this is part of the Theory of Relativity.

The relative part of relativity is where things come into play here. You’ve probably heard that if you’re on a rocket ship traveling near light speed, when 5 years pass for you, maybe 36 years will pass on Earth. That’s relativity in action. For you, it would never seem like you were somehow skipping ahead in time. You’re just traveling quickly. But relative to the people on Earth, you are traveling into the future. 

A fun example of this, that we saw in the real world, was the comparison between identical twin brothers Scott and Mark Kelly. Scott spent one full year in orbit, traveling at 17,500 mph in much lower gravity than his brother experienced on Earth. When Scott returned from orbit, Mark was 5 milliseconds older than he had been compared to his brother, thanks to the effects of time dilation. 

Experiments with atomic clocks in the 70s showed that those flown around the world on jets were off compared to those that stayed on the ground when they landed. The effect is the barest fractions of seconds and would never matter to a human during their lifespan, but it proves Einstein’s theory was true. More modern and even more precise clocks have confirmed this. 

GPS satellites, because of their speed and altitude, have to have specially adjusted clocks. They gain around 38 microseconds every day and need to be reset continually, or they would never work properly on Earth. Each day, they would give coordinates that were off by 10 kilometers if they weren’t adjusted. 

Time does travel differently based on relative conditions, and if we could achieve incredibly high speeds, the effect would be far more pronounced. You would, based on the observations of those you left behind, travel to the future. A hundred years could pass on Earth, but you might only age a few years, or even months, depending on the speeds achieved. 

What’s Stopping Us From Traveling to the Future?

The big speed bump, quite literally, in achieving time travel-type speeds is mass. As you increase your speed, your mass increases, and that means you need more energy. This is why nothing can travel faster than light. You’d need infinite energy to move your mass at the speed of light, and that’s just not possible. Light, which has no mass, travels as fast as possible.

So let’s say you want to travel at a fraction of the speed of light. You still need a lot of energy. Doubling your speed requires quadrupling your kinetic energy.  Tripling speed requires nine times the kinetic energy. 

Mathematically, if you want to move a 50 kg weight at 1% the speed of light, you need 200 trillion joules of energy to do it, which is the average daily energy consumption of two million Americans. This is by no means impossible, but it’s not super practical or easy to do. Plus, the average space shuttle weighs 2 million kg, so you need to up the energy used accordingly.

Another thing to remember about this kind of time travel is that you’re going somewhere. If you just wanted to loop around space and come back to the Earth in the future, you could theoretically do that, but you could never go back. The future by traveling close to light speed is a one-way trip.

Speed and Time

Traveling close to the speed of light is one way, theoretically, to get to the future. But a lot of time travel is focused on going back to the past. Is that possible at all? One theory says that you could if you could go faster than the speed of light, which we just spent some time explaining is impossible. Still, this is in the realm of the theoretical, so let’s just play with it. 

To an observer on Earth, if you were to leave in a vessel traveling faster than light speed and then return, the people on Earth would see the vessel returning, they see it leaving in reverse, and they’d also see it park right where it took off from all at the same time. It only gets more complicated from there. But none of it really takes you to yesterday. It just ensures you’re always here and also in space, and also traveling in reverse. 

Others, like Stephen Hawking, have argued that even if time travel into the past were possible, you could never travel to a time before you built the machine that let you travel back in time. It’s like saying you could never take the subway to any place that doesn’t have a subway stop.

Time Travel By Gravity

You may have heard that time slows down the closer you get to a black hole. Even if you were stuck on the Event Horizon of a black hole, time would stop completely. This has nothing to do with speed, but rather gravity. This is the other side of Einstein’s relativity coin. The more gravity, the slower the flow of time.

Time flows more slowly closer to the center of the Earth, and faster the further you get away from it. That’s partially why those atomic clock experiments work. It’s the Earth’s gravity affecting it. In theory, if we understood all the physics and had the technology to master it, we could use a black hole as a time machine. While minutes would pass in our time machine, years could potentially pass outside of the machine. You just have to make sure you don’t get pulled in, of course. 

This effect is fictionalized in the movie Interstellar, where a planet exists near a black hole and time is drastically altered. In reality, this would probably never happen, but, again, theoretically, maybe. 

Forward vs Back

So forward in time is possible in more than one way. But backwards? That’s a sticky wicket. The Laws of Thermodynamics don’t like reverse time travel because the universe can’t go back to the way it was. Things stay the same or they become more disordered over time; they don’t become more ordered, especially in the same way they used to be. 

Traveling back in time presents a world of paradoxes that are hard to puzzle out. The Grandfather Paradox, for instance. If you went back in time and killed your own grandfather, thus preventing one of your parents from ever being born, and in turn preventing you from being born, how did you go back in time in the first place?

One attempt to explain this away is that you obviously didn’t kill your grandfather, and if anyone ever did, they never existed for the rest of us, and that’s why we don’t remember them to know that they did. So it’s not a paradox, it’s just that, if you did it, you’d never know you did because you never existed, and no one ever knew you did to say differently. How’s that for a brain buster?

Another theory, which researchers feel is mathematically sound, suggests that any paradox you create would inevitably resolve itself by necessity. Basically, time corrects itself no matter what.

In practical terms, traveling back in time through any traditional means is simply not possible, according to most scientists. But there are non-traditional means out there.

Special Cases for Traveling Back

Einstein again gives us the possibility of a shortcut to traveling back in time. Wormholes, passages that allow spacetime to curve back on itself and take you back to a place and time that has already happened, are a theoretical possibility. Extremely theoretical, in that no one has ever seen one before, and we have no evidence they exist, it’s just that science doesn’t preclude their existence. 

Science fiction loves a wormhole because it makes travel through space and time convenient. And while an Einstein-Rosen Bridge sounds good on paper, we haven’t seen much evidence for one in real life yet. But space is vast, so you never know. More importantly, not everyone believes that, even if they did exist, they could be used to travel back in time. 

If a wormhole could go to the past, how would that work? One theory suggests a tube in space-time that connects a black hole to a white hole. Mathematically, a white hole makes sense and is just what it sounds like, the opposite of a black hole. While nothing can escape a black hole, nothing can stay in a white hole. It shoots out energy the way a black hole sucks it in. 

If a white hole connected to a black hole, the time dilation effect on one end could mean that, when you enter the hole, and when you leave the hole, are at vastly different times. So different, in fact, you could exit before you entered. 

The big problem here is that, to cross through this wormhole, you need to get past the black hole event horizon, and that’s not technically possible.

Another potential path to the past is cosmic strings. A “one-dimensional topological defect” created at the beginning of time itself, these strings could create closed time-like curves which could, in theory, let us go back to the past. 

A cosmic string theoretically formed when the universe was just being formed. As time and space and everything exploded out, there were little cracks or wrinkles, basically imperfections in the fabric of reality itself. Those are strings and, in theory, they can do a lot. If they date back to the beginning, and you could find one, you could ride that string back to any place in time. 

Of course, if these strings exist, they would be volatile beyond words. Extremely dense and packing almost immeasurable energy, these things would be like lasers cutting through anything that got in the way, time travelers or planets included. You’d have to learn to navigate around one very carefully to travel in time. 

If two strings crossed paths, a time machine could travel to the past along them. 

As you have noticed, the word “theoretically” pops up a lot here. Things that work in equations don’t always work in reality, and we are far from having the ability to test any of this. It would take centuries to even find a black hole with our current technology, for instance. Then we still need to figure out how to navigate one. 

Is time travel possible? Yes. We have even proven it with things traveling forward. But can we visit our ancestors, or the world of tomorrow, then be back in time for dinner? That’s looking like something that may never happen.

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How long can a person live? The oldest human ever, at least that’s been confirmed, was Jeanne Calment, who lived to see 122. So that is literally as long as a human can live right now until someone gets older. 

The average human lifespan is about 70 years but there are many factors that play into that all around the world including numerous diseases, malnutrition, war, and so many other things. Some geneticists believe 115 years is about all we could ever hope to get even under ideal circumstances, though Ms. Calment obviously spit in the eye of that idea.

These numbers are very much related to “natural” lifespan. But humans have a knack for taking nature and making it better (or worse). So, if we applied our brains, our technology, our science, what could we do? How long could a human live if we gave ourselves an assist? Would we ever have to die?  Let’s find out!

How Do You Get to Be the Oldest Human Ever?

In 2025, the oldest living person in the world is Tomiko Itooka, who is 116 years old. She has a ways to go to catch up with Jeanne Calment. But how does anyone live so long?  According to friends of Calment, she wasn’t just the winner of the genetic lottery, but you can bet that played an important part. She also had some other things going for her.

We won’t bury the lede on this one – Calment was rich. Rich people have a lot of advantages. She didn’t really work, she just socialized. She had a cook so she never even needed to think about what meals to make, and people did her shopping for her. She lived a life of leisure, by all accounts. She travelled the world, she saw the Eiffel Tower as it was being built, and she attended social functions. That’s not very stressful. And she took care of herself, because she had the time and the means.

In Japan, Ms. Itooka didn’t have as luxurious a life as Calment, but it sounded like a memorable one. In her younger years she was very active and was fond of hiking and climbing. In her 80s she even completed the Saigoku Kannon Pilgrimage which covers 33 different temples.

So let’s say, based on a very rudimentary reading of the lives of these two women, that longevity may be related to living a healthy, stress-free life. So simple! 

Change in Lifespan

Human lifespan has evolved considerably over the years. Everyone has heard the anecdotal idea that the average human lifespan was only 30 years a hundred years ago (or 200 years, or whatever fits that narrative). While that is not wholly inaccurate, life expectancy for someone born in the year 1900 was only 32 years, it also misrepresents the data. 

Average lifespans in the past were so low due to high infant mortality. If you live to 80 and your sibling died at birth then, between the two of you, the average lifespan was only 40 years. But, in reality, if you did survive to adulthood, then you probably lived a life not entirely different than you would in the modern world, at least in terms of duration. Most people survived well past 50. No one was elderly in their 20s.

Prior to 1900, 18% of children died before the age of 5. This was mostly due to infectious diseases, the sort of stuff we can vaccinate against now like measles and diphtheria. The infant mortality rate was around 10% and, in some cities, as much as 30%. That means 100 to 300 deaths per 1,000. In 2022, that number was 5.6 per 1000. 

As infant mortality improved, thanks to things like better neonatal health, vaccines, nutrition and sanitation, overall lifespan increases. Battling other conditions like heart disease has also improved the life expectancy in most countries. 

Covid took a big swing at global life expectancy and reversed almost a decade’s worth of progress. Numbers will probably go up again, globally, as long as trends continue the way they had been before the pandemic.

That said, if the growing antivax trend gets too much bigger, progress could be delayed or reversed even more. Vaccination rates dropped below 93% for some vaccines in 2022-2023. For 2024-2025 it’s likely the number will increase.

Charts showing the stunning success of vaccines when it comes to saving lives paint a very clear picture.  Over half a million people per year got the measles before a vaccine. After? 13. By March 2025, the CDC had confirmed 222 cases in the United States. All of this is going to lower the natural lifespan of Americans moving forward.

Theories on How Long You Could Last

So if 122 years is the absolute best we’ve ever done, and in the last few years we’ve actually started backsliding because of poor decisions and novel diseases, what’s next? Can we hope for better?

To start with, it’s worth remembering that this all has to be speculation. Because, again, 122 years is the best anyone has ever done. And she did it without any help from cybernetic body parts, nanotechnology, altered genetics, or alien DNA. That said, there are experts in the field out there who believe a human can potentially live for a thousand years. Just try to imagine how much you would hate that.

João Pedro de Magalhães, a professor of molecular biogerontology, thinks we could wipe out aging on a cellular level based on his study of long-lived animals. If we do that, we could crack 1000 years. Or even something absurd like 20,000 years. What’s the science behind it? He doesn’t know. But he does believe we could invent it. Fair enough!

Others look at aging and death as two separate things that we wrongly link. Aging doesn’t lead to death, at least in the eyes of some. It’s just that the longer you live the more likely you are to die of something. So, theoretically, with improvements in medicine and technology, our life expectancy could continue to dramatically increase the way it did from the 1900s to now.

Of course, not everyone believes we can live forever. Some pick 120 to 150 as the range as the most we can ever hope for because disease and other hallmarks of aging will drag you down at that point no matter what you try. Bayesian statistical analysis has led some researchers to narrow it down further. The next “oldest” person in the world will likely make it between 125 and 132 years. 

Striving for Immortality

Improvements in healthcare, medications, quality of life in general, are technically scientific advancements. But, when we ask could science help you live forever, is that really what we mean? No. You’re hoping for something much more dramatic. 

When you think about science letting you live forever you’re thinking about genetic engineering or robotic body parts or something like that. Gerontologist Aubrey de Grey famously declared that the first person who will live to see 1,000 has already been born. So let’s look into the world of speculative science and see what it has in store for us.

We know there are creatures in the world that are functionally immortal right now. Something like the hydra comes to mind. This little life form is made out of stem cells so that it can keep renewing itself pretty much indefinitely.  You can put a hydra in a blender, mulch it into a liquid, and the cells will reform into a living creature again.

Humans, however, are more complex. We can’t be only stem cells. If our cells constantly renewed like a hydra, we could not be complex life forms. Imagine if your neurons kept replacing themselves. Everything in your mind, your personality, your memory, all of it, would never form in the first place and if you ever did form something, it would vanish again as the cells regenerated. 

Our cells have a limited time to them before they become senescent, which is to say worn out. Your cells do replicate, but only for so long. In time they just stop. They end up dying. You sort of grind down. 

Some believe the key to getting past 120 years is nanobots. If our cells can repair themselves like those of a hydra, then we give them a helping hand. Microscopic robots in our bloodstream programmed to destroy cancer cells as they form, or repair red blood cells so they don’t break down. 

Nanobots could maintain hormone levels, keep our brain functioning at peak levels, ensure organs never suffer any slowing or disease. They would, again in theory, eliminate anything that normal slows or limits a human body as it occurs.

If you are never slowed or never limited, then what could possibly kill you other than something sudden and out of your control? There would be no such thing as a “natural” death again. Only accidents or homicides.

Of course, since the human body has about 37 trillion cells, this process is easier said than done. That’s a hell of a lot of maintenance to put on technology that doesn’t even exist yet. 

Nanobots are not alone as being the potential bringers of immortality. Genetic engineering also offers some hope in terms of changing how we age. If we can alter the way our DNA ages, we can extend our lives. CRISPR technology could allow us to edit our genes and work around diseases and degenerative conditions.

 Another potential kind of immortality comes with abandoning the flesh. If you believe who you truly are exists in your mind, then what if you could upload your mind into a computer? Either into the cloud, or maybe even a robot designed to look like you. 

If your mind could be transferred, fully and completely, that could be considered a kind of immortality. From your perspective, you would still be there. And, theoretically, this process could be done indefinitely even as your new artificial body falls apart after hundreds or thousands of years. As long as there’s still materials to make new bodies, what would stop you from continuing forever?

This idea sounds far-fetched, but scientists have already accomplished something similar. Not on such a grand scale as a human, but the mind of a roundworm was put into a Lego robot and a Lego robot started acting like a roundworm. That’s going to be the most terrifying sentence you hear all day, or the most amazing one. That happened all the way back in 2014, incidentally. 

Can We Live Forever?

It’s an interesting question, to be sure. Could a human live forever? Or could we live 500 years? 1,000 years? The number of people who have suggested there are potential ways to extend our lives almost indefinitely seems encouraging, at least in terms of answering the question. But it’s also worth remembering that all of these different methods that might lead us to long life spans are speculative.

In much the same way someone can tell you about all the ways you could become a millionaire, the practical application is quite a bit different from the reality. They’re not even necessarily telling you something that’s untrue, it’s just knowing how something could happen and making it happen are often two very different things. In the end, we’ll know it works if it ever works. Until then, all we can do is keep speculating.

In London’s Imperial War Museum, a team staged a curious experiment: they fed a modern AI the problem that haunted Alan Turing during the darkest days of World War II and get a result in the time it takes to have a cup of coffee.

This is a reminder of how far computing has come. But it’s also a big question mark for where encryption goes from here on.

Apparently Less Enigmatic Nowadays

The Enigma machine, with its three rotating rotors and a labyrinthine plugboard, was Nazi Germany’s pride. It was considered to be one of their symbols of invulnerability. When German generals tapped out encrypted messages each morning, they trusted that the ever-changing complexity of their code—different settings each day, no letter ever mapping to itself—would be more than the Allies could solve.

That confidence wasn’t absurd. The mathematics behind Enigma was daunting. Each rotor could be set to one of 26 positions, and combinations of plugboard wiring created over 150 quintillion possible configurations.

“The number of possible ways in which a message could be encrypted was astronomically large,” Prof. Michael Wooldridge, a computer science expert at the University of Oxford told The Guardian. “Far, far too large for a human to exhaustively check.”

Cracking the Enigma was a mammoth challenge. That’s why it took Turing and his colleagues at Bletchley Park months to gain a foothold. After the groundwork laid by Polish mathematicians, the British team built their own machines—nicknamed “bombes”—which automated the brute-force search for valid Enigma settings. At peak efficiency, they could decrypt about two messages per minute. But every second mattered in times of war, and the cracking of the Enigma code was a pivotal moment.

“To be able to crack it—it took them months, more than a year—but to be able actually to do this within the lifetime of the war, it was a huge thing,” said Dr. Mustafa A Mustafa, a senior lecturer in software security at the University of Manchester. “God knows what would have happened if we hadn’t cracked Enigma in time.”

Modern Machines, Ancient Ciphers

Fast-forward 80 years. What took bombes hours, modern processors dispatch in moments. One AI model, trained on German using Grimm’s Fairy Tales and aided by 2,000 cloud servers, decrypted a four-rotor Enigma message in just under 13 minutes.

Unlike the rigid methods of Turing’s day, this AI used probabilistic reasoning—comparing decrypted outputs to patterns in the German language. “The AI was trained to look for German language, and then work out the statistical probability of the sentence decrypted being the accurate original,” Lukasz Kuncewicz, Head Data Scientist at Enigma Pattern, the company behind the demonstration, told Tech Radar.

Wooldridge added that the whole process could be replicated even more efficiently using contemporary computing models. “It would be straightforward to recreate the logic of bombes in a conventional program,” he said. “Then with the speed of modern computers, the laborious work of the bombes would be done in very short order.”

That doesn’t mean Turing’s legacy is diminished. Far from it. His pioneering work cracked a wartime code and laid the foundation for the very computers that render it obsolete today. He is, after all, considered the father of artificial intelligence.

“The bombes were crude hardwired mechanical computers,” Wooldridge noted. “And the power of modern datacentres is hard to imagine. Enigma would not remotely be a match for these.”

The problem is how our modern encryption stands up to potential attacks.

What does this mean for encryption?

While cracking of Enigma might seem like a historical footnote, it raises pressing questions for today’s digital age.

If AI can unravel what was once unbreakable, what codes remain secure?

For better or for worse, encryption systems like RSA keep the internet secure for now. But RSA was developed in the 1970s and based factoring large prime numbers, so it’s hard to tell how long it will still hold — especially with quantum computing just around the corner!

“In the case of RSA, it’s the problem of factoring very large numbers. Brute force techniques—looking through all the alternatives—just won’t work on these problems,” Wooldridge said. “If quantum computers ever deliver their theoretical promise, then we may need completely new techniques to keep our data safe.”

This is no longer the domain of spies and generals. As AI becomes more capable, the same techniques used to crack Enigma could potentially be turned on passwords, personal data, and secure communications. “It’s like a knife,” Kuncewicz said. “It can save lives or it can take lives.”

For now, most AIs require human oversight. The AI used in the Enigma test still needed engineers to check that it hadn’t gone off-track—declaring nonsense as meaningful. But this boundary is becoming increasingly thin.

Would Turing be amazed? Perhaps. But he might also have seen it coming.