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See NEOWISE (CosWatch Blog 7)13/07/2020

Welcome to the seventh of Fun Science‘s CosWatch blog posts, which you can read through with your young scientist and learn how to see the comet NEOWISE.

This comet is visible for about the next week, but then will be absent for thousands of years. Unless you’re immortal or a ghost, don’t delay!

What is CosWatch?

There’s so much to see in the night sky! You may have seen Brian Cox on TV describing the “wonders of the universe”, or Carl Sagan talking about the “awesome machinery of nature”, and they’re absolutely right. But while huge rockets and observatories can help, space isn’t just for people with expensive equipment. You can see amazing things from millions of miles away from your very own back garden. Each week, I’m going to talk about one of these incredible objects, and how you can find them.

This time, we’re going to be talking about how to see NEOWISE, a comet visible this month!

Tell me about NEOWISE

Comets are balls of ice that move around the solar system, which is why they’re sometimes referred to as “dirty snowballs”. NEOWISE is one of these comets.

Comets move around in strange oval orbits. When they move close to the Sun, they begin to melt, and large amounts of their ice are torn off in the form of bright gasses. This is why they have long tails.

This image from Wells & Mendip Astronomers shows us NEOWISE’s tail.

NEOWISE has a strange name because it was discovered by the NEOWISE space probe. The “WISE” stands for “Wide-field Infrared Survey Explorer”, while the “NEO” stands for “Near-Earth Object.”

https://upload.wikimedia.org/wikipedia/commons/thumb/9/94/WISE_artist_concept_%28PIA17254%2C_crop%29.jpg/1280px-WISE_artist_concept_%28PIA17254%2C_crop%29.jpg

The probe in question. This is just concept art, but gives us a good idea of what the probe looks like in space.

Where do comets come from?

There are two types of comet – “short period” comets, that orbit the Sun in less than 200 years, and “long period” comets, that take much longer than that – sometimes many thousands of years.

https://upload.wikimedia.org/wikipedia/commons/thumb/1/10/C_2020_F3_NEOWISE.jpg/800px-C_2020_F3_NEOWISE.jpg

As this diagram demonstrates, NEOWISE is a long period comet; it takes about 4500 years to reach us, and another 6800 to get back to where it started from.

Short period comets are thought to originate from the “Kupier Belt”, a ring of asteroids past Neptune. Long period comets probably come from the “Oort Cloud”, a great cloud of gas and rock that surrounds the Solar System.

https://space-facts.com/wp-content/uploads/oort-cloud.png

A diagram by Lorine Moreau showing the incredible size of the Oort Cloud – you can also see the Kupier Belt.

We have tried to land some space probes on comets, ocassionally successfully. However, because of the relatively small sizes (often about that of a city) and extremely high speeds involved, mistakes do occur. A lander from the Rosetta spacecraft managed to reach a comet, but unfortunately bounced underneath a cliff; this meant that its solar panels were uesless, and the batteries ran out before many results could be acquired.

How can I see NEOWISE?

NEOWISE will be very, very difficult to see after the 19th, and will disappear soon afterwards. There’s also the risk of it breaking up into pieces too small to see at any point. Don’t delay! Make plans!

I managed to see NEOWISE at 3:15am on the 12th. Yes, unfortunately this CosWatch will involve some early morning rising or late nights – but for such a rare spectacle, isn’t it worth it?

https://cdn.discordapp.com/attachments/698261768455061535/731684347039580170/unknown.png

This photograph was taken by my good friend James in London, and should give you some idea of what you’ll be seeing.

Some people have reported seeing NEOWISE as early as 11:30pm, but for security’s sake, 3am – before it starts to get dark – is your best option. Find somewhere with a clear view of the North-East horizon. It should be fairly difficult to miss, but if you’re having trouble finding it, locate the star Capella using the internet or star charts, then look further down.

NEOWISE is visible with the naked eye, but in areas with considerable light pollution, it’d be worth using a binoculars or a telescope; unlike shooting stars, comet, though extremely fast, look like they’re moving very slowly aross the sky, and are easy to focus on as a result.

In conclusion:

  • NEOWISE is a comet visible for the next week or so.
  • It is a “long period” comet, meaning it takes thousands of years to move around the solar system.
  • It probably originated in the Oort Cloud.
  • Its tail is simply ice melting as the comet approaches the Sun.
  • You can see NEOWISE easily – but not for long!

What’s next on CosWatch?

Next time, I’ll be talking about Saturn, the iconic ringed gas giant. Have fun observing NEOWISE!

Notes:

Fun Science recently created a “Planets and Space” home kit, pre-orderable now for only £5.00. Check it out here!

See Uranus (CosWatch Blog 5)01/07/2020

Welcome to the second of Fun Science‘s CosWatch blog posts, which you can read through with your young scientist and learn how to see Uranus.

What is CosWatch?

There’s so much to see in the night sky! You may have seen Brian Cox on TV describing the “wonders of the universe”, or Carl Sagan talking about the “awesome machinery of nature”, and they’re absolutely right. But while huge rockets and observatories can help, space isn’t just for people with expensive equipment. You can see amazing things from millions of miles away from your very own back garden. Each week, I’m going to talk about one of these incredible objects, and how you can find them.

This beautiful shot from Voyager 2 captures Uranus’ colour… but that might be the least interesting thing about this mind-blowing planet.

This time, we’re going to be talking about how to see Uranus, the second-to-last planet in the solar system!

Tell me about Uranus

Uranus is the seventh planet from the Sun, and takes a staggering eighty-four years to go around it; for every “month” of Uranus’ year, seven years have passed on Earth! Like Jupiter, it is a gas giant, meaning  it is mostly made of gas. Also like Jupiter, it has a short day of only seventeen hours and fourteen minutes.

I love this art by Stefan Blaser, which shows us how an astronaut would see Uranus from the surface of its moon Umbriel.

There’s something absolutely fascinating about Uranus which makes it totally unique. If you look at art of photos which show Uranus’ rings, you’ll notice they seem to be upright, rather than sideways. There’s a delightful reason for this – the entire planet is sideways! Nobody is quite sure why Uranus is this way.  Research suggests that when the Solar System was forming, the early Uranus was hit by an object larger than Earth, which pushed it over.

Uranus: The Ringed Planet That Sits on its Side | Space

This more distant image of Uranus demonstrates its tilted axis, and some of its moons.

Uranus has at least 27 known moons, mostly named after Shakespearean characters such as Ophelia, Cressida, Margaret and Puck.

Discovery and name

Uranus is even more distant than the first six planets. It wasn’t even identified as a planet in ancient astronomy, only as a star. That changed in 1781, when William Herschel discovered it – from the city of Bath, no less. Not only that, but its orbit helped Astronomers realise that there must be an eighth planet – Neptune was discovered sixty years later!

William Herschel working at his telescope, from which he’ll see Uranus. His sister Caroline would go on to make many discoveries of her own.

Astronomers didn’t agree on a name for almost seventy years. Rather than continuing the trend of naming the planets after Greek/Roman Gods, Herschel wanted to name the planet “George’s Star”, or Georgium Sidus, after his King. People from other countries didn’t want a planet named after an English King, and called it other names. One of the more popular names was Herschel, after its discoverer.

Unfortunately for Herschel (but fortunately for people who like good names for planets), Astronomers eventually settled on “Uranus”, after the Greek god Ouranos. Now, many people mock Uranus’ name because “anus” is another word for bottom, but most agree it’s a better name than George’s Star.

How can I see Uranus?

Uranus is more difficult to see than the more well-known first six planets, which is why it wasn’t recognised by astronomers for so long. It can be seen with the naked eye on a moonless night, but you’re better off setting up a telescope or binoculars. It will appear as a blue-green smudge; if you’re lucky, you’ll see some moons too. You can buy special filters to make it more visible, but these aren’t necessary.

Uranus will spend all of 2020 “in” the constellation of Aries the ram. It’s being shy at the moment, spending a lot of time hiding under the horizon where you won’t be able to spot it. I like the website timeanddate.com for this – using their “night sky” function, you can choose your location and planet, then simply test visibility for each of the nights.

Sadly, Uranus has chosen to hide from us tonight – but will be visible soon!

Uranus is my favourite planet without life, and I can’t wait to observe it soon. Stargazing is the perfect lockdown activity. It’s relaxing, it’s best done far away from people other than your family/housemates, yet it connects you to everyone on Earth. I hope you enjoy it!

In conclusion:

  • Uranus is the unusual seventh planet from the Sun, and the third gas giant.
  • It is flipped onto its side, with vertical rings.
  • Uranus has 27 moons, mostly named after Shakespeare characters.
  • Uranus was discovered in the 1700s in Bath, and Astronomers argued over its name for nearly 100 years.
  • You can see Uranus with the naked eye if you’re lucky, or fairly easily with a telescope.

What’s next on CosWatch?

Next time, I’ll be talking about the Andromeda galaxy, the most distant and large object so far on CosWatch. See you soon!

Notes:

Fun Science recently created a “Planets and Space” home kit, pre-orderable now for only £5.00. Check it out here!

In this article I describe Uranus as a gas giant. In fact, along with Neptune, it is a special type of gas giant called an “ice giant”. All that means is that it has lots of gasses other than Hydrogen and Helium.

Younger scientists, or older ones with good taste, may want to check out The Magic School Bus Lost in the Solar System in Joanna Cole’s Magic School Bus series to help them remember and learn about the different planets – though note that this book has Pluto classified as a planet, which is of course out of date..