By Tyler DeWacht
Hello, and welcome back to Space News! Last time, I covered all news relating to the Sun, the center of our Solar System. In this edition, we’re going from the center all the way to the farthest reaches of our tiny area of influence within this vast universe. This is what news we have from the outer reaches of the Solar System.
First off, let’s check in on the cosmic race between the objects leaving us, those that have hit escape velocity. Up in front we have the Voyager 1, moving at 62,000 km/h. Following behind in third place is the Voyager 2, moving at nearly 58,000 km/h. Until an even faster competitor enters the race, the Voyager 1 probe will forever hold the number one spot. Despite them being over 48 years old and over 20 billion kilometres away, the two Voyagers still regularly maintain contact with Earth.
However, this won’t be the case for much longer; the nuclear batteries that power them are losing energy, and they’ll have to start shutting down the scientific instruments of Voyager 1 in 2020 in order to conserve power. Most estimates state it won’t survive past 2025. Voyager 2 is facing the same predicament, and it may even fail sooner because it now has trouble picking up radio frequencies. Once they lose all power, they’ll be left to fend for themselves in interstellar space. Barring any collision, however, the probes themselves will survive millions of years without decay, and perhaps some alien civilization will someday stumble upon the Golden Records contained within.
Following behind the Voyager probes are the Pioneer 10 and 11 probes in second and fourth place respectively. While the Pioneers did have a 5-year headstart, the perfect timing of the Solar System alignment made it so that the Voyagers would gain faster speed. Pioneer 11 failed in 1995, while Pioneer lasted until 2003, so we can only guess their current positions. However, it is predicted that the Voyager 2 will overtake Pioneer 10 sometime in April 2019, stealing second place. Like the Voyagers, they also have a message from humans to aliens, this one in the form of a plaque. Despite being the first to launch, they will eventually fall into last place, since they’re also moving at the slowest pace.
The newest entry into the race is the New Horizons spacecraft, which recently had a rendezvous with Pluto. Thanks to that, we now have pictures of the dwarf planet as well as its main moon Charon. It also captured images of the smaller Plutonian moons Nix, Hydra, Kerberos, and Styx, albeit not in ideal image quality. Yes, Pluto has five moons, it’s not just Charon. New Horizons is currently in fifth place, not surprising given that it was only launched in 2006. It is set to eventually overtake the Pioneer probes, but this won’t happen until well within the 22nd century, and it will never overtake the Voyager probes.
So, now that it passed Pluto, where is New Horizons off to next? The next destination for New Horizons will be a small Kuiper Belt object nicknamed Ultima Thule, which refers to a cold and speculative land that is farther north than north itself, a place beyond our known world. Quite appropriate, considering it will be the farthest object we’ve yet had the opportunity to examine close-up (the Pioneers weren’t designed for this task, and we didn’t know the Kuiper Belt existed until 1992, when the Voyager probes had already passed through the area).
Once through the Kuiper Belt, what happens next? Well, there appears to be a wall of hydrogen between us and interstellar space, as New Horizons has been indicating. Research is undergoing, but one hypothesis is that the solar winds of our Solar system are blowing up against some interstellar winds, keeping our hydrogen trapped near the edge of the heliopause. As Voyager 1 passed through the area in 2013, it appeared to show similar findings with what is being detected today. If it is indeed the case that this wall marks the outer edge of our Solar System, then this means that Voyager 1 is now the first man-made object in interstellar space.
However, there is supposedly one more layer beyond this wall: the Oort Cloud. We have yet to confirm its existence, but the Oort Cloud is said to be a thinly-dispersed collection of comets and stray asteroids that have been held captive by the fringes of the Sun’s gravitational field. Perhaps it also holds the elusive Planet Nine, who knows? Anything out there would receive hardly any sunlight, and temperatures approaching absolute zero would be the standard. With our current technology, it would take sheer luck to find even one object that far out. We can’t wait for our solar escapees to reach it either; even at the Voyager 1’s current rate of speed, it would still take at least 300 years to even get close, and it just doesn’t have that much time left. It’s possible that some Kuiper Belt objects with odd orbits were originally from the Oort Cloud, but we’d have no way to identify which is which unless we know the common properties of both groups. Neither us nor our children or even our grandchildren will make much progress with this area, so we may just have to keep this goal on the sidelines until a future generation finally develops practical means to more closely examine the Oort Cloud.
Does this mean our dreams of exploring other stars is also doomed? Not necessarily. There is a project in development called Breakthrough Starshot which aims to send Starchip spacecraft to the Alpha Centauri star system. It would take less than thirty years to complete the trip, and the spacecraft would be moving close to 20% the speed of light, making the Parker Solar Probe look like an interstellar snail in comparison. How, you may ask? Not with rockets, those are too slow. Instead, it will be propelled by a beam of light aimed at ultra-thin lightsails. With no air or water to push against, this interstellar boat will exponentially increase speed. This extreme speed also comes with a downside: it can’t stop easily. Precise navigation will be very difficult, and the slightest impact would completely destroy the Starchip. In order to minimize the latter, it will have to be small and streamlined enough to miss most objects. It’s either that or we send as many as we can and hope a few make it. You can see how this would be a problem if we want to use this technology on future manned missions.
Interstellar flight within our lifetimes may seem like an impossible dream, but they also said landing on the moon was impossible. Caltech scientists have been able to engineer a sail out of silicon and silica that can withstand those insane speeds. A laser shoots photons at the sail, and nanotechnology woven within monitors the light coming in contact with it so that the craft doesn’t accidentally overheat. Many people the world over are still working on the problems of such an ambitious project, but there’s still at least 30 years before we’ll be able to put any of these plans into motion, so let’s just see what the future holds.
We may not be able to leave yet, but that doesn’t mean others can’t enter. We have our first confirmed interstellar visitor, except it’s not an alien but a rock. Is it a comet or an asteroid? We don’t know, it’s been acting weird. Oumuamua is a strange cigar-shaped rock hurtling through our Solar System, and we’re trying to learn more about it. The most we know right now is that it couldn’t possibly have come from our Solar System and that it seems to defy conventional standards for matter formation in space. Where did it come from, where will it go? As it leaves at an unexpectedly fast rate, astronomers are still scrambling to find more answers. We may yet be able to catch it with a probe, but we’d need to quickly get something ready, and there are more urgent matters at hand, so it doesn’t seem likely. Until another passes by, we may just be stuck for answers.
That about wraps up the current news from the edges of our Solar System. Next time on Space News, the gas giants Jupiter and Saturn will get their time in the spotlight. As you gaze at the cosmos, consider your future here on Earth and forge your own path forward among the stars.