Which Astronomical Events Will I Never Get To See? | Unveiled

Which Astronomical Events Will I Never Get to See?

For as long as humans have been gazing into the night sky, we’ve been frankly fascinated. The distant stars, the moving planets, the sun, and the moon – there’s a reason why so much meaning is given to the heavens in mythology, in religion, and in modern-day science. But much as we would like to, it’s impossible to witness all the incredible events the universe has to offer in just a single human lifetime.

This is Unveiled, and today we’re answering the extraordinary question; which astronomical events will we never get to see?

We all know that space is, well, huge, which makes it a difficult business predicting the future events that will happen to it. And yet, we’ve been doing it for centuries. What’s widely considered the first-ever computer, the Antikythera Mechanism, for example, was built by the Ancient Greeks to chart the movements of planets and predict eclipses. Truth be told, pumping data from the sky into any kind of algorithm is almost always going to demand a massive margin for error; there’s just so much about space that really isn’t that predictable at all. But equally, there are various events that are - as far as we understand them - a sure thing… it’s just that, barring some sort of near-future, anti-aging, major scientific breakthrough, everyone alive today won’t be alive to see any of them happen!

In the twenty-second century, Halley’s comet will reappear, as it does roughly every seventy-five years. Though there are people alive today who witnessed its last passage past Earth in 1986, and plenty will see it return in 2061… in 2134, this world-famous space spectacle will be seen by a new generation, most of which won’t before have had the pleasure. There will be more cause to celebrate in 2177, too, when Pluto reaches its first anniversary in the eyes of humanity – that’s one Plutonian year, or 248 Earth years, since it was discovered. Maybe people in the twenty-second century will hold “Pluto Parties” to mark the occasion!

In less favourable news, there are plenty of near-earth asteroids set to speed through the solar system over the next few centuries - with some predicted to pass uncomfortably close to our planet. One particularly close call could happen in the year 2880, for example, when the asteroid 1950 DA - which has been charted by astronomers for decades already - is predicted to just barely miss us. The likelihood of it actually colliding with Earth is still thought to be less than one percent, but that could change as we move closer to the time, and tensions could rise over the years between now and then.

As we move into the next millennia, future humans will witness other exciting transits, too. While Mercury transits in front of the sun about thirteen times a century in one of the solar system’s more regular happenings, there will be a handful of times in the next few thousand years when Mercurian transits will coincide with solar eclipses - a much rarer phenomenon, next predicted to happen in the year 6,757.

Long before that happens, though, we’ll have said goodbye to one of the most defining and important features of the night sky; the north star. As the brightest star in the Ursa Minor constellation and a constant indicator of which way is north, the north star, Polaris, is vitally important for navigation. And, as early as March 24th 2100, it’ll appear the furthest north it’s ever been and ever will be. But, by the year 3000, Polaris will have had its “north star” crown stolen by Gamma Cephei - as the night sky shifts from our perspective. After that, we’ll go through a series of other north stars, as future astronomers look to other objects to guide them… including the currently lesser-known stars Deneb, Vega, and Thuban. Polaris will eventually make a triumphant return, however, in the year 27,800. So, in more than twenty-seven thousand years’ time, our far, far, far future ancestors will again read the sky as we do now.

While some of these events might not be immediately obvious to a casual observer, though, much of what space has in store for us certainly will be… including one spectacular scene scheduled to happen at some point in the next 100,000 years; the death of VY Canis Majoris, one of the most luminous stars in the Milky Way. When it goes supernova, stargazers on Earth will almost certainly know about it, witnessing bright pulses as this one-time star transforms into a new black hole (albeit a black hole much too far away to physically affect us).

At some point in the next 100,000 to 500,000 years, Betelgeuse, the tenth brightest star in the sky, will also meet an explosive end. And, this time, the effects might register to some degree here on Earth. At just 700 lightyears away from us, it’s much closer than Canis Majoris, so it’s death will constitute a “near-Earth supernova”, which is a supernova between 30 and 1,000 lightyears away. Anyone on Earth at the time would see Betelgeuse glow considerably brighter, but it’s not thought that the event would cause any lasting damage here; we may need to brace for a small burst of radiation, but that’s all. Even so, if and when Betelgeuse goes, it’ll amount to a seriously rare event; it’s estimated that in the last eleven million years, there have been only twenty near-Earth supernovae - it’s just not something you see every day!

Maybe you don’t want to see a supernova, though. Maybe you want to see another living star up close and astronomically personal. In that case, any observers who happen to be in the solar system in around 1.29 million years’ time will be treated to the flyby of Gilese 710, an orange dwarf star expected to drift within less than one lightyear of the sun… that’s more than four times closer to the sun than the current next-nearest star, Proxima Centauri, and close enough to significantly disrupt the Oort cloud - the predicted cluster of rock and ice which encases the solar system. And anything which messes with the Oort Cloud could mean a major increase in local asteroids to worry about!

In six million years’ time, the comet Catalina, which has one of the longest orbital periods ever discovered (and was first discovered in 1999), will return for only its second flyby in human history – or perhaps its first flyby in the history of whatever post-human species is around at the time. Even further on, and Phobos, one of the two moons of Mars, will finally be destroyed by its host planet’s gravity. Already, Phobos is falling apart, but these things take time in the grand scheme of space… and for any Martians that emerge in the next 30 to 50 million years – which is roughly when Phobos will finally meet its doom – the destruction of one of their moons will surely be an important event.

For an even more spectacular show than even a near-Earth supernova, the demise of a nearby moon or the close approach of a brand-new star, however, we’ll have to wait 2.4 billion years for the Milky Way to devour a neighbouring galaxy. The Large Magellanic Cloud is a satellite galaxy of our own, and it’s already visible from Earth in parts of the southern hemisphere. In billions of years’ time, though, the Milky Way will absorb it. But despite being the fourth-largest galaxy in the local group, and despite having “large” in its name, the Large Magellanic Cloud isn’t actually that big for a galaxy. And, just a couple of billion years after it merges with the Milky Way, something even more substantial will happen when, in 4.5 billion years from now, the Milky Way and Andromeda finally collide. This collision in itself will play out over billions of years as well, and while it’s unlikely that the cosmic merger will have any destructive implications for our solar system, it will be visible in the sky for a long time - as a new elliptical galaxy that’s already been christened by some as “Milkdromeda” gradually forms.

Unfortunately, there won’t be much of Earth left by this point, so anyone or thing still alive to watch the galaxies collide will have to do so from someplace else. It’s estimated that in 2 to 3 billion years (if not sooner), the slow expansion of the sun will have rendered Earth much too hot to support almost all life. Then, in 4 to 5 billion years, just as Andromeda lights up the sky, the sun will begin to grow into a red giant as it starts to die. In 7.5 billion years’ time, the sun will have bloated so much that Earth – and all the other inner planets – will have been swallowed up. Now, the icy moons of Jupiter and maybe Saturn, really could be the only even relatively nearby places where life would have even a slim chance of survival. But the death of the sun wouldn’t mean the end of the solar system.

When the sun finishes expanding, it will shrink back down into an extremely dense white dwarf star. And then, while this stellar remnant may technically be dead, it’ll take billions and billions more years for it to cool down enough to become a black dwarf. The process is so long, that it’s thought that no black dwarfs currently exist in the universe; they’re still a hypothetical construct, only. However, there are some suggestions that it would be possible for life to form in a white dwarf system, in the meantime… which means that new planets could eventually exist where we are now, with lifeforms on them thinking about how they weren’t around to witness the death of the old sun, the supernova of Betelgeuse, the passing of Catalina, or any of the rest of it. Maybe.

Of course, these futuristic inhabitants of the solar system will also have missed plenty of things that we have already witnessed, too. For decades now, the moon landing has stood as a cultural milestone, for example, but in the far future the moon probably won’t exist anymore, either (having also been caught up in the sun going red giant!). in the near future, if various plans come to fruition, then we could also see the first Mars landing… but that too would represent just a small speck in the history of space by the time we get to the solar system being centred around a white dwarf star!

Really, what we can learn from all of this is that our local section of space is always and forever changing but it’s also not unique. Here, just like everywhere else in the universe, amazing and spectacular events take place all the time. It’s been happening for billions of years since the Big Bang and it’ll continue for billions of years after humans, and even the Earth, are gone. And those are the astronomical events we’ll never get to see.