Wonders of the Universe

THE UNIVERSAL CHEMISTRY SET

Surprising as it sounds, we know what every star, planet and moon in the observable Universe is made of, despite the fact that there is only one other place in the Universe that humans have actually visited in person.

On 21 July 1969, Neil Armstrong and Buzz Aldrin became the first humans to set foot on another world. They spent 2 hours, 36 minutes and 40 seconds walking on the surface of the Moon, but it wasn’t until the last half hour that they carried out one of their most important scientific tasks. Using basic geological tools, Buzz Aldrin drove two core tubes into the lunar surface to collect the most famous rock samples taken in history. By the time they’d finished hammering and scooping up samples they had collected 22 kilogrammes (47 pounds) of lunar treasure. After using a pulley system to lift their scientifically priceless cargo on board, they closed the hatch and went to bed. As the two astronauts slept alongside the precious lunar rocks, the United States could justifiably claim to have won the greatest and arguably most glorious political victory in human history. For one rare moment, a political victory was also a triumph for all mankind.

However, it is not widely known that as the Apollo 11 lunar module rested on the Moon, a Soviet spacecraft was also in lunar orbit. The unmanned Luna 15 was the Soviets’ third attempt to land on the Moon and collect lunar rock samples. Launched three days before Apollo 11, Luna 15 was a last-ditch attempt to win the scientific race to return rock samples from another world. Unfortunately, although Luna 15 successfully began its descent to the Moon’s surface, it crashed into it shortly afterwards. Only Apollo 11 returned with moon rocks, which continue to be analysed to this day in the high-security labs of the lunar sample building in Houston, Texas.

Despite forty years of study, one thing has been clear pretty much from the start: these priceless examples of alien geology are remarkably similar to rocks found on Earth. In the main, they are composed of the common rock-forming elements oxygen, silicon, magnesium, iron, calcium and aluminium, but there is absolutely nothing on the Moon’s surface that couldn’t be found here on Earth.

Since Apollo 11’s success, we have landed on Mars and Venus, parachuted into Jupiter’s atmosphere, touched down on Saturn’s moon Titan, and visited asteroids Eros and Itokawa and the comet Tempel 1. Each time the story is the same; the Solar System is made of the same stuff as we are. To date, eight landings on our nearest neighbour, Mars, have allowed us to explore the planet’s geology in intimate detail. We now know Mars is rich in iron, which has oxidised to form its familiar rusty red colour, and that Martian soil is slightly alkaline and contains elements such as magnesium, sodium, potassium and also chloride. We also know that Venus’ thick atmosphere is full of sulphur, and the planet Mercury is a large metal ball of iron with a thin crust comprised mostly of silicon. Even at the very edge of the Solar System, billions of miles away from Earth, we have discovered that Neptune is rich in organic molecules such as methane, a substance we find in abundance on our planet. Again and again we find there is much to discover in our solar system, but there are never new elements to unearth. From a scientific perspective this is unsurprising, because long ago Mendeleev’s table revealed there isn’t any room for other light elements in nature – we have discovered the full set. It would take a change in the laws of physics to discover something on the surface of another world that doesn’t fit into Mendeleev’s scheme, but from the explorer’s perspective, seeing is believing!

On 21 July 1969, Neil Armstrong and Buzz Aldrin became the first humans to set foot on the Moon. This successful landing also opened up infinite possibilities for scientists to understand the formation of the lunar landscape. This photo shows Aldrin collecting some of the lunar rock samples that they took back to Earth for analysis.

NASA

The Apollo 11 lunar mission was launched from the Kennedy Space Center, Florida, on 16 July 1969 and safely returned to Earth on 24 July 1969, complete with its priceless cargo of samples from the Moon’s surface. The first container was transferred to Ellington Air Force Base and was taken directly to the Lunar Receiving Laboratory at the Manned Spacecraft Center (MSC) in Houston, Texas.

Once safely returned to Earth, the treasures from the Moon, including rock samples, were painstakingly analysed at a high-security laboratory, and are still being used for analysis today.

NASA

Again and again we find there is much to discover in our solar system, but there are never new elements to unearth.

This false-colour photograph of Neptune was taken by Voyager 2. This image has enabled scientists to discover that the planet is rich in organic molecules such as methane.

So what about the rest of the Universe? How universal are these elements across the far reaches of the cosmos? Could it be that there are places in the distant Universe where the laws of physics are different? This is a legitimate question – we shouldn’t simply assume that everything at the edge of the visible Universe, billions of light years away, operates exactly as it does here, no matter how persuasive the arguments from theoretical physics. Experiment and observation are the ultimate reality check. It may seem impossible to presume that we could ever answer this question directly and discover what the stars are made of, because they are so far away (they may indeed remain untouchable forever), but in fact we knew what the stars were made of long before we got our hands on that first piece of lunar rock