Image: The Pillars of Creation 2014 – NASA (Public Domain)
Ah, space; it has dominated the imaginations of the young and old alike for generations. Since the very first days of our species, humans have looked to the stars and wondered “what on Earth might be up there?” These days, with the scientific equipment both up there and down here on Earth, it seems we learn about new wonders every day. Just following NASA or ESA on Facebook will provide you with enough beautiful images that you’ll never be without a phone wallpaper again. Have you ever wondered though what these spectacular sights are, or how they came to be?
“Where are we in the universe?” seems like an almost pointless question. The universe is pretty big, so how do we narrow it down? We know we are in the solar system, a collection of planets and other stuff orbiting the star, but what structure is that a part of? The solar system, as many of you will know, lies in the Milky Way galaxy, a collection of billions of stars and planets. This might be enough for some, but to ensure our mail gets delivered, the next line on our address is the local group. This is a collection of over fifty galaxies, big and small. It includes our nearest galaxy, Andromeda, which we will someday crash into quite spectacularly.
“The question of how many planets there are in the solar system is one that can cause some tension in die-hard astronomy circles.”
After the local group comes the Virgo supercluster, a concentration of galaxy groups like ours. This contains thousands of galaxy groups and clusters and, until recently, that was where the address ended. In 2014 however, astronomers published a new way of analysing superclusters, and discovered that we are a part of one more even greater structure – the Laniakea Supercluster. This sprawling concentration of stars contains over 100,000 galaxies and innumerable stars and planets and is one of the largest structures in the known universe. It makes getting lost on campus seem a small problem by comparison.
The question of how many planets there are in the solar system is one that can cause some tension in die-hard astronomy circles. When we were growing up there were nine planets, then one day there were eight. Poor Pluto. In recent years though we have been looking beyond our own solar system for planets. This process was helped by the Kepler mission, which analyses far-off stars for signs of orbiting planets. To date it has discovered over 1000 confirmed extra-solar planets, or exoplanets. Few are more interesting though than Kepler-452b, or as it has been perhaps presumptuously nicknamed, Earth 2.
What makes Kepler-452b interesting is that it is the most Earth-like planet found to date. It is 60 per cent larger than Earth and orbits its star every 385 days, but even better, it lies with its star’s habitable zone. The habitable zone is the area around a star within which a planet can contain liquid water – necessary for life as we know it to flourish. If we were to ever settle on a different planet, those in habitable zones would be the first choices. This doesn’t mean that “Earth 2” is suitable for life: because of how far away it is, not much can be known of its surface, but even if it is a rocky planet it may have a greenhouse effect similar to Venus. Chances are we won’t find out though; it lies 1,400 light years away. Our fastest travelling space probe, New Horizons, would take over 26 million years to reach it.
The other planets within our own solar system may not be habitable, but they each have interesting features. Mercury is the smallest and nearest the sun. Venus is the only planet named after a woman, the Roman goddess of love and beauty. Mars appears red due to the amount of iron oxide present on its surface. Jupiter is the largest planet within our solar system and has at least 67 moons. Saturn is usually depicted with a hula hoop surrounding the planet. Although not the only planet to have a ring system, Saturn’s rings are more prominent than any other planet. Uranus has the coldest atmosphere in the solar system at -224.2°C. Neptune is the furthest planet away from our sun, and in fact, takes 164.79 years to orbit the sun.
There is a theory that it can rain diamonds on Jupiter and Saturn. Lightning can liberate carbon molecules from methane which clump together as soot. Under the great atmospheric pressure of the planets’ atmospheres, the soot is compressed into diamonds. But, when it comes into contact with high temperatures of 8000°, the diamonds liquify and diamonds rain down onto the planet below.
“This photo, taken by the Hubble Space Telescope, shows three majestic pillars of dust and gas, with the light from newborn stars streaming through them.”
One of the most famous images of space is of the Pillars of Creation. This photo, taken by the Hubble Space Telescope, shows three majestic pillars of dust and gas, with the light from newborn stars streaming through them. The Pillars are part of a gigantic cloud made up of molecular hydrogen and dust. This cloud is what is known as a “stellar nursery”, an adorable term for an area where stars are in the process of being formed. The hydrogen and dust starts to clump together under gravity, which in turn causes more gas and dust to be attracted together. When the mass becomes heavy enough, the hydrogen at the core starts to fuse together, releasing light and heat and is from then on known as a star. As the Pillars are approximately 7,000 light years away, the stars we see have aged a little by the time their light reaches us, but they are still only in the infancy of their more than billion year life cycles.
Unfortunately, the Pillars themselves might not have such a long existence. Images of the region show clouds of superhot dust which may have been caused by a supernova. The power from such a blast would destroy the Pillars – in fact, they may already be gone. Light can only travel so fast, and the images would have the blast occurring six thousand years ago. If this is the case, we may point a telescope at the Pillars of Creation in a thousand years time to find them gone.
In the great space outside our planet lies so many fascinating and beautiful wonders. So, the next time you’re outside at night time, preferably outside of the city, look up, and allow yourself to marvel at the amazing universe we live in.