Answers: Name That Rocky World
- 14th Feb 2017
- Author: Tamela Maciel
There have been some truly stunning images coming back from spacecraft around the Solar System recently. Rather than focus on one world or photograph, how about a little game of Name That Rocky World?
Below are six images that give an up close and personal view of different rocky bodies in the Solar System.
Think you recognise them? Send us your answers as comments to the relevant posts on our Facebook or Twitter pages, or email us direct at spacecomms@spacecentre.co.uk. Major space kudos to anyone who gets all six right!
UPDATE 14 Feb 2017: Warning! Answers below! Click here for the original, answer-free post to play the game.
1. Comet 67P/Churyumov–Gerasimenko
Cliffs towering 900 metres straight up and a rugged foreground strewn with boulders create a haunting scene on this rocky world.
Photo captured October 2014.
Answer: This scene is a close-up of the looming cliffs of Comet 67P/Churyumov-Gerasimenko, as captured by the Rosetta spacecraft when it was only 10 kilometres away back in October 2014. The Rosetta mission revolutionised our understanding of comets. No longer are they simply ‘dirty snowballs’, but instead living, breathing worlds with cliffs, chasms, and molecules such as water, oxygen, and amino acids. It’s possible that a comet such as 67P introduced these essential building blocks of life to primordial Earth billions of years ago. The Rosetta mission came to an end on 30 September 2016 after more than two years at a comet.
2. North pole of Mars
Swirling layers resemble an iced bun on this world. The layers are thought to be sculpted by strong winds.
Mosaic images captured between 2004 and 2010.
Answer: This sculpted landscape is the north pole of Mars! It’s a recently-released image compiled from images captured by the European Space Agency’s Mars Express mission. You’ll notice we were deliberately tricky by converting the tell-tale red image to black and white.
Mars’ north pole is permanently covered by layers of water ice and carbon dioxide ice (i.e. dry ice) in an area that spans nearly a million square kilometres. Strong winds twisted by the Coriolis force of Mars’ rotation are thought to sculpt the ice into swirling patterns and dark trenches.
In the winter, the north pole is in permanent darkness and up to 30 percent of the carbon dioxide in the Martian atmosphere freezes and snows onto the cap. In summer, this process reverses, creating seasonal strong winds and carbon dioxide geysers.
3. Europa
Fractured ridges and channels tell a dynamic history of the surface of this world.
Image captured November 1997.
Answer: This ice world is Europa, one of Jupiter’s four Galilean moons. The colour version was captured by NASA’s Galileo mission, which circled Jupiter for eight years between 1995 and 2003. The criss-crossing ridges and cracks indicate a dynamic world below. One of Galileo’s major discoveries was the possibility of a liquid water ocean below Europa’s icy crust, a place that could potentially harbour life.
This discovery was actually the cause of Galileo’s demise, inadvertently. Rather than risk introducing Earth-born microbes that may have piggy-backed on the Galileo spacecraft, the mission controllers decided to deliberately crash the spacecraft into the clouds of Jupiter at the end of its life, removing the possibility of future contamination.
4. Pluto
Jagged mountains rising up to 2.4 kilometres high end abruptly at a wide, fractured plain.
Image captured July 2015.
Answer: When NASA’s New Horizons spacecraft flew past Pluto in July 2015, it captured a hitherto unknown world at the edge of our Solar System. Before New Horizons, this Hubble image was the most detailed shot we had of Pluto. Now we have this intimate view of jagged peaks of water ice rising kilometres above ‘lava-lamp’ frozen nitrogen plains.
Pluto may no longer be classified as a planet but the activity and variety of this frozen world are no less fascinating.
New Horizons is now enroute to an object in the Kuiper Belt known as 2014 MU69 and due for arrival on New Year’s Day 2019.
5. The Moon
Jagged hills rising 2 kilometres high are the striking, sunlit centrepiece in this rough terrain.
Image captured June 2011.
Answer: This is a close-up of the peaks in the centre of the Moon’s Tycho Crater, beautifully lit by the rising sun and captured by NASA’s Lunar Reconnaissance Orbiter in 2011.
The Tycho Crater is an impressive 82 kilometres across, with 4.7 kilometre high sides. The mountains in the middle rise 2 kilometres high, formed from rebounding material just after the impact that formed the crater. But the most important statistic about this lunar crater is its age. At only 108 million years old, Tycho Crater is the new kid on the block and its fan-like ejecta is still bright and obvious in the southern hemisphere of the Moon.
6. Earth
This impact crater spans 1.2 kilometres across, created by an iron-nickel asteroid that slammed into this world about 50,000 years ago.
Image captured June 2007.
Answer: Were you fooled by this one? It’s planet Earth! More specifically the Meteor Crater (or the Barringer Crater) near Flagstaff, Arizona. Even Earth is not immune to large impacts from asteroids and comets, as is evident from this 1.2 kilometre wide crater. It’s estimated that this crater was formed 50,000 years ago when an iron-nickel asteroid measuring 46 metres across slammed into the Earth.
Erosion and weather on Earth has partially filled this crater, whereas on the Moon and other atmosphere-free worlds, the craters are virtually permanent.
