Using Telescopes, Spectroscopes & Probes to Investigate the Universe

Instructor: David Wood

David has taught Honors Physics, AP Physics, IB Physics and general science courses. He has a Masters in Education, and a Bachelors in Physics.

Humans are explorers. It's exciting, but it also leads to great discoveries about the universe. Learn how we use telescopes, probes and spectroscopes to investigate the universe.

Investigating the Universe

Humans have been interested in exploring for as far back as we know. Whether it's Neil Armstrong walking on the Moon, or Captain Cook sailing across the world, exploring the unknown has always been inspiring to us. But it isn't just about piquing our curiosity. Exploring also expands our knowledge and expertise.

Tallships Once Explored the Oceans
Tallships Once Explored the Oceans

When we investigate and explore the universe, we're often faced with new technical challenges. Putting a man on the moon was an incredibly difficult prospect in the 1960s, and took all our know-how to achieve. However, even less dramatic challenges like building gigantic mirrors for telescopes has influenced human advancement.

And then there's what we discover in the process. When we learn about what's out there, we often discover new and surprising things. As we figure out how to explain those things, we can find ourselves dealing with brand new sciences that nobody could have imagined. The incredible technologies around us: cars, TVs, computers, and cell phones are the kinds of things that we come up with when we use that knowledge. Investigating the universe has had a huge impact on how humans live.


One of the first ways we investigated the universe was simply observing it using telescopes. Telescopes are made to magnify large, distant objects so that we can see them as if we were up close. At first those telescopes used glass lenses, and later mirrors. At first we looked at visible light, but then we expanded to other parts of the electromagnetic spectrum like radio waves, or microwaves, or x-rays.

At first we only used telescopes on Earth, but then came the Hubble Space Telescope that flies in orbit, removing the effects Earth's atmosphere has on the light we receive. With each step forward we get better and better images, and learn more about our universe.

The Hubble Space Telescope
The Hubble Space Telescope

We've learned too many things to name thanks to telescopes, ever since Galileo first used one to view the moons orbiting around Jupiter. But perhaps the most significant was discovering the sheer magnitude of the universe. The Earth might seem huge, but compared to the universe it is tiny. Not only does our solar system contain eight planets, but the Sun is only one of 100 billion stars in our galaxy. And our galaxy is one of at least 100 billion galaxies in our universe.

It's even possible there are other universes. Compared to all that, it can make our existence seem small. But it also makes you think: if so much can be happening on the tiny speck that is the Earth, just think how much could be happening elsewhere in the universe!

Image from the Hubble Space Telescope
Image from the Hubble Space Telescope

Probes and their Equipment

Even if we can't always send humans to explore, we can send probes. Since the late 50s, humans have launched dozens of probes to investigate the planets and moons of our solar system. As of 2015, only Uranus and Neptune haven't been properly investigated, though Voyager 2 did fly by them on its way to the outer reaches of the solar system.

The Famous Voyager Probe
The Famous Voyager Probe

These probes can carry all kinds of equipment to help them make discoveries. These can include spectrometers, radiometers, thermometers and cameras. Spectrometers are particularly common and important; they measure the composition of a substance. Spectrometers have been used to measure what planets' atmospheres are made of, what the solar wind is made of, and what rocks on Mars are made of. Once we have that information, we can use it to figure out what happened over the history of each planet.

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