Comets and the Oort Cloud

We say the solar system is made of the Sun and 8 planets, but there’s so much more to it than that. Billions of objects and billions of kilometres, it’s unbelievably large.

Chart showing orbit route of comet C/2017K2

Tanno and Iguda visited this comet when it was much closer to the Earth than shown in this chart.

But it was far enough away that it hadn’t developed a ‘tail’ yet. The classic comet image shows it with gases trailing out away from the Sun and scattering the light like a sunbeam. Like you can see in this animation.

This animation of a comet’s tail might take a while to load, but it’s great when it does. It takes a while for the data to be sent back to Earth!
Image Credit: NASA/JPL-Caltech

Most comets come from way outside the orbit of Neptune, and even beyond the Kuiper Belt in a space called the Oort Cloud.

The Oort Cloud is ginormous.

It begins 1,000 times further from the Sun than the Earth is, and goes on to a distance 100,000 times further away. You thought it was a long way down the road to the chemist…

On a background of stars,

NASA’s NEOWISE mission discovered a comet in March 2020. They called it C/2020 F3.

The picture shows three images on top of each other. You can see all the stars are the same, except the red dot which has moved to a different position in each. This is C/2020 F3 moving across in front of the stars.

The pictures were taken using infrared light, and the different colours show different temperatures of objects. This new comet is much colder than the hot stars and galaxies that show up white. The tiny red dots are bits of dust – not as cold as empty space, nor as hot as a star.

Image Credit: NASA/JPL-Caltech

Tanno and Iguda discovered that the Universe is so large it’s difficult for us to even understand how large that is. But how did they know when they were home in our solar system? Where is its edge?

Activity

Comet exploration. Make a poster that explains all about what comets are made from, their orbits, and what we have done to explore them.

Your poster should include examples of at least three comets and at least two missions to explore them. You could print out pictures to illustrate your poster, or design it on a computer and copy them across from website research.


Look out for the incredible PostcardsFrom… series about Earth.

Coming soon: PostcardsFromVolcanoes, PostcardsFromArtists

Check out what series are available by clicking here.

You can go to the previous DeepSpace secret pages by clicking the places below.

Distant UniverseBlack HoleDark Matter
GalaxiesSupernovasNeutron Stars
These delicate wisps of gas make up an object known as SNR B0519-69.0, or SNR 0519 for short. The thin, blood-red shells are actually the remnants from when an unstable progenitor star exploded violently as a supernova around 600 years ago. There are several types of supernova, but for SNR 0519 the star that exploded is known to have been a white dwarf star — a Sun-like star in the final stages of its life. SNR 0519 is located over 150 000 light-years from Earth in the southern constellation of Dorado (The Dolphinfish), a constellation that also contains most of our neighbouring galaxy the Large Magellanic Cloud (LMC). Because of this, this region of the sky is full of intriguing and beautiful deep sky objects. The LMC orbits the Milky Way galaxy as a satellite and is the fourth largest in our group of galaxies, the Local Group. SNR 0519 is not alone in the LMC; the NASA/ESA Hubble Space Telescope also came across a similar bauble a few years ago in SNR B0509-67.5, a supernova of the same type as SNR 0519 with a strikingly similar appearance. A version of this image was submitted to the Hubble’s Hidden Treasures Image Processing Competition by Claude Cornen, and won sixth prize.
Blue Ring NebulaBetelgeuseExoplanets
Alpha CentauriArrokoth
Composite image of Arrokoth (kuiper belt object 2014 MU 69) showing it's one object made from two lumps of rock like a snowman.