In August this year, we passed the 45th anniversary of the launch of NASA’s Voyager 2 spacecraft – the sister of Voyager 1, which also launched in 1977. The Voyager probes, and particularly Voyager 2, were transformative to the way we view the Solar System. Voyager 2 became the first (and thus far only) spacecraft to visit the Ice Giant planets – Uranus and Neptune – in 1986 and 1989, respectively. Today, the veteran probe continues to speak to us from a staggering 130 Astronomical Units (AU) away. That’s 130 times greater than the distance between the Earth and the Sun. Its sister, Voyager 1, is even farther from us at over 157 AU distant!
Artist’s impression of Voyager passing Uranus, created for NASA in 1981.
NASA/JPL/Don Davis
Voyager 2 passed Uranus a little over two centuries after the planet was first discovered by William Herschel from his home in Bath. To say that is rapid progress would be an understatement. Herschel identified Uranus as an object of interest in 1781, decades before the first electric motor was built and nearly a century before the lightbulb. Yet just over 200 years later, his new planet – nearly 1.8 billion miles from the Sun – was brought into sharp relief. For all its achievements, the Voyager programme was much closer to the beginning of interplanetary exploration than the era we now find ourselves in, and so much more has been done. In 2015, New Horizons completed the reconnaissance of the old school nine-planet system when it rendezvoused with Pluto for a brief flyby. Months before in the tail end of 2014, The Rosetta spacecraft successfully deployed a probe (Philae) to the surface of a comet. Almost a decade earlier, in 2005, the Huygens probe touched down on Titan – Saturn’s largest moon – having hitched a ride to the ringed planet with Cassini. The pace of exploration has accelerated, and today’s picture of the Solar System is incredibly diverse. Every question answered has generated two more, so it’s no surprise that the Solar System remains a fertile area of research for cutting edge missions.
The Jupiter system is revealed in stunning detail by the James Webb Space Telescope. This infrared image shows the planet’s rings, auroras and two of its faint moons.
Are we destined to one day populate these faraway worlds; to spread out and occupy every corner of the Solar System? It’s an enduring concept in science fiction storytelling about the spacefaring future of our species, but nature hasn’t’ accommodated for it. We’ve evolved on the surface of a genuine haven – planet Earth – and every other place in the Solar System is astonishingly hostile by comparison. But humans have a pioneering spirit. We crave adventure. The path to becoming an interplanetary society, however difficult, is too alluring to ignore. Another anniversary is now looming, and it’s motivating NASA to push out into the Solar System once more. In December, we’ll celebrate 50 years since the last crewed mission to the Moon. Apollo 17 put two astronauts on the lunar surface in 1972, before bringing them home. They would leave the last human footprints on the surface of our celestial neighbour as the Apollo programme came to end. Now, Apollo’s twin sister Artemis is the namesake for the next generation of lunar missions, which will establish a permanent presence on the Moon: a moon base and an orbiting space station called Gateway. At the time of writing, the SLS awaits its maiden flight Artemis I, from Cape Canaveral. In 2024, Artemis II will take a crew of astronauts around the Moon. After five decades, we’re going back not just for a visit, but to learn to live on other worlds.
The magnificent Space Launch System (SLS) rocket stands on the pad at Kennedy Space Centre.
In many ways, we’re retaking our first steps again and a human presence on Mars, or indeed anywhere else beyond the Moon, is still a long way away. For the time being, most of us will stay bound to the Earth and our exploration of the Solar System will be a remote affair. But there’s so much to uncover from the comfort of your own home. Great storms erupting on Jupiter; the shimmering rings of Saturn; broiling sunspots on the solar surface; eclipses, conjunctions and meteor showers… it’s enough to keep any budding astronomer busy, and your first views of the remote Ice Giants, or fine rugged details on the face of the Moon will be no less impressive than they were to Herschel, Galileo or the many other pioneering observers of the last few centuries.
The Solar System is a treasure chest, most of which is just over the horizon of visibility to the unaided eye. Yet even a modest pair of binoculars can partially reveal its mysteries, and a telescope is the key to a wealth of incredible sights. In my latest guide I’ve shared all my experience to help you get started with observing these treasures yourself. It contains information about what to look for, how to get the best view and even how to take your own images just like the pros do. It’s a comprehensive introduction to the destinations of tomorrow.
Observing Our Solar System: A Beginner’s Guide is now available from Collins, providing a comprehensive introduction to exploring the Moon, Sun, planets and much more with your eyes, binoculars, and telescopes. Discover the history of Solar System science, the highlights of our neighbourhood, special events and more.
Tom Kerss is an astronomer, astrophotographer, writer and speaker, specialising in the rewarding task of connecting people to their shared universe. He is the author of Northern Lights, Moongazing, Stargazing and You Can Explore the Universe, all of which are available now.
His new book, Observing Our Solar System, is out now.