How Form 2220 Ting 2023-2024

The city sky is frankly rather boring. If you look up at the patches of murk between buildings, you might be able to pick out the Big Dipper or perhaps Orion's belt. But hold on, look at that murky patch again and hold out your thumb. How many stars do you think are behind it? 10? 20? Guess again. If you looked at that thumbnail-sized patch of sky with the Hubble Space Telescope, instead of points of light, you'd see smudges. These aren't stars, they're galaxies, just like our Milky Way. Cities of billions of stars, and more than a thousand of them are hidden behind your thumb. The universe is bigger than you can see from the city, and even bigger than the starry sky you can see from the countryside. This is the universe as astrophysicists see it, with more stars than all the grains of sand on earth. By staring up at the stars at night, you've taken part in the oldest science in human history – the study of the heavens. It is older than navigation, agriculture, perhaps even language itself. Yet, unlike other sciences, astronomy is purely observational. We cannot control the parameters of our experiments from lab benches. Our best technology can send man to the moon and probes to the edge of the solar system, but these distances are vanishingly small compared to the yawning gulfs between stars. So how can we know so much about other galaxies? What they're made of? How many there are? Or that they're even there at all? Well, we can start with the first thing we see when we look up at night – the Stars. What we are trying to learn is their properties. What are they made of? How hot are they? How massive? How old? How...