The curiosity inciting exploration of the unknown has long been ingrained in our species’ genetic make-up, egging us to seek knowledge of what lies beyond the horizons we call home. Once we had conquered the ability to explore most of our planet’s surface with relative ease, it was only natural that our gaze would turn towards the vastness of the heavens we look out into every night. Humanity looked, and humanity wondered what could possibly lie in store beyond our tiny rocky planet; past the bubble of air which swathes our planet, keeping us alive. Being the explorers we inherently are, how could merely observing the tiny dots of light in the sky ever have been enough?
2019 marks 50 years since humanity’s venture to the Moon – the only body other than Earth which, to this day, has seen members of our species land on its surface. The Moon landings, though lauded for the achievement and perseverance which they represent (and, of course, berated as false by conspiracy theorists), were far from the only ventures which humanity has undertaken to extend its horizons. In the absence of the necessary tools to send astronauts further away from our pale blue dot, unmanned missions to other worlds have numbered beyond counting.
Our colder neighbour, Mars, has been the target of dozens of missions in its own right, with several successful landings to boot. Today, spacecraft have been sent to visit, even if just for a quick flyby, all the planets in our solar system. Notably, the Cassini spacecraft orbited and studied the Saturnian system for just over 13 years, and the Galileo spacecraft orbited Jupiter for eight years. Voyager 1, which is now the furthest man-made object from Earth, had visited both the Jovian and Saturnian systems while Voyager 2 had also visited the Uranian and Neptunian systems. Until 2015, Voyager 2 did in fact hold the record for the furthest flyby ever (Neptune), but this changed with the arrival of New Horizons at Pluto.
It took New Horizons nine years to complete its journey from Earth to Pluto, reaching the dwarf planet on July 14, 2015. The mission provided us with our first ever views of the mysterious Kuiper belt object, and redefined our knowledge on icy bodies in the outer reaches of our solar system. Notwithstanding its record-breaking flyby, however, New Horizons’ journey was not yet over. Living up to its name, the spacecraft sought to unveil yet another, further, new horizon for humankind. Its path was intended to fly by yet another, even smaller Kuiper belt object – (486598) 2014 MU69, or as it is more commonly known – Ultima Thule.
New Horizons’ flyby of Ultima Thule occurred just over a month ago, on New Year’s Day of 2019. Images now received from the spacecraft show the furthest world we have ever observed up close, over 43 times the distance of the Earth from the Sun. Ultima Thule is actually a contact binary, with two distinct bodies in contact with each other, just over 31km long combined. The flyby confirmed that the shape of Ultima Thule was in fact irregular, with a long and elongated shape postulated for the Kuiper belt object upon its discovery in 2014, typical of contact binaries. It is thought to have formed from numerous planetesimals which coalesced first into the two smaller bodies forming the contact binary, before these lost momentum and eventually came into contact, fusing to form Ultima Thule.
Josef Borg is currently a PhD student within the Institute of Space Sciences and Astronomy, University of Malta, and also the president of the Astronomical Society of Malta.
Did you know?
• Voyager 1 will come ‘close’ to another star in about 40,000 years. Although it is not heading towards any particular star, Voyager 1 will actually come within about 1.6 light years of the star Gliese 445 in about 40,000 years. It will of course have ceased to function long before then, with estimations putting Voyager 1’s communication lifetime at around 6 more years. However, both Voyager spacecraft will most likely travel around the Milky Way for a very long time.
• Pluto sports a heart-shaped feature on its surface. Thanks to close up images of the dwarf planet in 2015, surface features on Pluto could be easily distinguished with immaculate detail for the first time. One such feature, called Tombaugh Regio (named after Pluto’s discoverer, Clyde Tombaugh), contains what is thought to be a basin of frozen nitrogen and carbon monoxide, among other ices.
• New Horizons was the fastest man-made object ever launched from Earth. The spacecraft launched at a neck breaking speed of 16.26km/s, or around 58,500km/h, making it the fastest man-made object to be launched to space. Even at this speed, however, New Horizons still required a gravity assist from Jupiter to further increase its speed in order to make it to Pluto in nine years!
For more trivia see: www.um.edu.mt/think
Sound bites
• NASA Probe Snaps 1st Photos from Just a Mile Above Asteroid Bennu: NASA’s OSIRIS-REx mission is orbiting an asteroid closer than any spacecraft has ever orbited a body, and it shows in an incredible pair of photographs that the team released on January 24. The spacecraft slipped into orbit around the asteroid, called Bennu, on December 31, after the team carefully mapped the object to design a safe path for the probe. That was a challenge, since Bennu is the smallest space rock that’s ever been orbited.
https://www.space.com/43129-asteroid-bennu-one-mile-photos-nasa-osiris-rex.html
• Chinese Companies OneSpace and iSpace are preparing for First Orbital Launches: Chinese private companies OneSpace and iSpace are making progress with plans to attempt their first orbital launches in the first half of 2019. OneSpace is currently working toward a launch of its OS-M rocket that could come as early as late March, following engine tests for the four stages of the launch vehicle in the second half of 2018. The company will soon proceed with comprehensive electrical systems and payload fairing separation tests as next steps toward launch.
https://www.space.com/43142-china-companies-onespace-ispace-orbital-launches.html
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