There are lots of ways to remember the eight planets on our solar system.
But it’s also easy to spot them in the sky for yourselves; and today we’re going to show you how!
The word ‘planet’ originates from the
Ancient Greek meaning “wanderer” because planets never stay still. Over the course
of months, they wander across our night skies against a backdrop of static, twinkling stars.
So you could observe every single point of light in the sky, night after night, looking for the ones
which move over time. But you’d need the patience of an Ancient Greek Astronomer.
So what if you want to know where the planets are going to be tonight?
You can visit your local planetarium to get some amazing stargazing tips, but another great
resource is right in your pocket. There are lots of free stargazing apps available
to download, such as ‘Sky Map’, ‘Planets’ and ‘SkyView’, which use augmented reality
to map out constellations, satellites and planets.
Just point your phone at the sky and you’ll be able to tell whether that orange dot is Mars or Jupiter.
Pretty soon, you'll be able to pick out the planets amongst the familiar patterns of the constellations.
Which is a pretty good party trick to show your friends. Trust me, I'm the life and soul.
Only on a clear night mind.
Now, from Earth you can spot Mercury, Venus, Mars...
Jupiter! Eh! Saturn!
But if you want to spot Neptune or Uranus, you're going to need a trusty pair of binoculars, or a telescope.
And definitely no light pollution.
But what if you want to find planets outside of our solar system?
There are two main methods, the first one is called 'Radial Velocity'.
And this works on the principle that just as stars gravitationally attract planets,
So do some planets have a force of attraction on their stars.
And so as a high-mass planet is orbiting a star, it is pulling that star toward it.
Just a little bit. But using sensitive detectors and powerful telescopes on Earth,
We can detect that pulling by observing a star wobbling left and right, just a little bit.
We can also detect exoplanets using something called the 'Transit Method'.
And this is very similar to what we're seeing today with Mercury.
So this is a photo that was actually taken a few hours ago by a solar observatory.
And this tiny disc here is the planet Mercury, and it's passing across - it's 'transiting' - the face of the Sun.
And as seen from Earth, we can see that as a tiny black disc.
But when this happens around other stars, our telescopes aren't good enough to be able to get pictures like this.
But using sensitive detectors, what we can do is detect the dipping in brightness of the star
Because the planet is blocking some of the light.
And by doing that we can make some determinations about the properties of the planet.
We can work out roughly how big it is, and roughly how far it's orbiting from a star.
And from that we can infer its composition and its mass.
How many exoplanets might actually be out there?
We've discovered more than 2,000 already, but that's just the tip of the iceburg.
There are bound to be billions out there.
So observatories can find exoplanets with specialist equipment,
Could I find an exoplanet? See an exoplanet from my back garden?
Unfortunately, not yet. The technology hasn't come down to the consumer level; maybe in a few decades.
But if you do want to help out exoplanet hunters, then you can go to a website called 'planethunters.org'
And on there, you'll find loads of data that's been gathered about the transit method around other stars.
And there's so much information now that professional astronomers need help to make sense of it, to look through it all.
And you can go onto that website, take part in a short tutorial that will tell you everything you need to know.
You can analyse real data and maybe you can discover an exoplanet.
If you enjoyed this video hit like, share it around and click on my transiting planet to subscribe.
Check out our beginners guide to astrophotography;
and if you take any pictures of the night sky, be sure to share them with us on Facebook or Twitter.
Thanks for watching!
But what if you wanted to find planets outside of our solar system?
I 'De Niro-ed' again! [laughing]