If the sun were made of bananas, it wouldn’t make much difference. That’s because the sun is hot on account of the mass of material crushing down on its interior, not its composition. The sun is a billion billion billion tonnes of mostly hydrogen. But put the same mass of bananas in one place and it would be equally hot. (Why it stays hot is another matter!)
Photograph: © NASA / Planetary Visions
NASA spent $20bn on sending men to the Moon – trillions of dollars in today’s money. But the American space agency missed the biggest photo opportunity of all time: there is no photograph of the first man on the moon, Neil Armstrong. The second man, Buzz Aldrin, failed to take one
Photograph: © NASA / Planetary Visions
Want to see a Martian? Look in a mirror! Mars, being smaller than Earth, cooled earlier after its formation, so microbial life may have arisen there first and then been transported to Earth. Many meteorites have been found which were ejected when big bodies slammed into Mars. Living things could have survived inside these interplanetary travellers on the journey to Earth.
• The credit on this image was amended on 15 January 2010
Photograph: © ESA, DLR, and FU Berlin
Imagine a storm which could swallow 100,000 Hurricane Katrinas and has been raging not for days, but for centuries. Jupiter's Great Red Spot, which may have first been seen as early as 1655, boggles the imagination. The Red Spot’s colour may come from chemicals like phosphorus which are dredged from below
Photograph: © NASA / Planetary Visions
Beneath the coloured ice of Jupiter’s moon Europa is a body of water which is probably the biggest ocean in the solar system. Who knows what may be down there, swimming in total darkness, warmed by sea-floor volcanic vents?
Photograph: © NASA / Planetary Visions
The body in the solar system which generates the most heat for a given volume is not the sun, but Jupiter's 'pizza' moon, Io. The moon is hot for the same reason that a rubber ball gets hot if you repeatedly squeeze it, only in this case it's Jupiter's gravity that's doing the squeezing
Photograph: © NASA / Planetary Visions
Galileo is one of the giants in the history of science, but one of the low points in his career came when he turned his telescope on Saturn and declared it was 'a planet with ears'. His telescope just wasn't powerful enough to show the planet was in fact girdled by a system of rings
Photograph: © NASA / Planetary Visions
Everyone knows that the planet Saturn has rings, right? Space probes have revealed thousands upon thousands of them. Well, actually, the so-called rings are in fact spirals – like the grooves on an old vinyl record
Photograph: © NASA / Planetary Visions
When the German musician William Herschel discovered a new planet from his garden in 1781, he called it George (well, “George’s star”). The French objected to a planet named after an English king, George III. But the Germans were the peacemakers, suggesting a compromise which has stuck ever since – Uranus
Photograph: © NASA / Planetary Visions
Mars is home to the biggest mountain in the solar system, Olympus Mons. Three times the height of Everest and the area of Italy, its lava-producing crater, or 'caldera', is roughly 70km across and bordered by cliffs up to 3km high
Photograph: Nasa
