Shooting Stars & Meteor Showers

Par Jean-Marc Richard Pavillon d’astronomie Velan

Shooting Stars & Meteor ShowersShooting stars invite us to observe the night sky and discover the beauty of the heavens.

Shooting stars remind us - the Earth is like a space ship in orbit around the Sun - and that our planet is not alone in its annual voyage...a voyage which has been going on for 4.5 billion years.

Every August, Earth’s undeviating orbit allows us to view, the heavenly spectacle of the Perseids …a deluge of shooting stars which we call a meteor shower.

Before we go any further... Please know you can win prizes: 1) by drawing on your knowledge of astronomy and powers of deductive reasoning 2) by listening carefully

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Natural Objects in SpaceDifferent types of natural objects come from outer space and penetrate the Earth’s atmosphere.

• Comets (ice, rock & dust) • Asteroids (metals & rock) • Meteoroids (rock) • Meteors • Meteorites

Asteroids, meteoroids, meteors, & meteoritesAsteroid: a large rocky body in space, in orbit around the Sun.

Meteoroid: much smaller rocks or particles in orbit around the Sun.

Meteor: If a meteoroid enters the Earth's atmosphere and vaporizes, it becomes a meteor, also called a shooting star.

Meteorite: If any part of a meteor survives the fall through the atmosphere and lands on Earth, it is called a meteorite.

Comets & AsteroidsBefore we look at shooting stars and meteor showers, lets examine 2 types of natural objects from space that can also enter Earth’s atmosphere.

• Comets

• Asteroids

Comets & AsteroidsComets :

Where do they come from?

They originate from an immense cloud of natural objects that surround our solar system.

CometsComets :

Composed of ice and debris.

Up to several kilometers in diameter.

CometsComets:

The Sun’s gravity attracts these frozen objects and they begin a long voyage towards the Sun.

As comets approach the Sun, they leave behind a long plume of dust and plasma.

CometsComets:

- The comet will round the Sun...and follow a course back to the outer frontier of the solar system.

- It will then restart its journey back towards the sun.

- This will take tens, and in some cases hundreds of years.

A Picture of a Comet in 2007.

Be a Prize winner!

“Who can name a comet that passes by the Earth?”

Come up with an answer and win a prize...

Be a Prize winner!

“Who can name a comet that passes by the Earth?”

1 Halley’s Comet (passes Earth every 75 – 76 years)

2 Hyakutake (passed Earth in 1996. Has a 570 million km tail)

3 Hale Bopp (passed Earth in 1997. Last visit - 2000 BC)

CometsComets:

- Sometimes the gravity of the Sun is stronger than the mass and speed of the comet.

- In these cases, the comets do not escape the pull of the Sun and crash into it.

CometsComets:

- Jupiter, the second largest objet in our solar system after the Sun, offers us some protection.

- Because of its strong gravitational pull, it attracts comets like a giant vacuum cleaner.

CometsComets:

In 1994, 28 fragments of the Shoemaker-Levy 9 comet crashed into Jupiter.

AsteroidsAsteroids:

- The majority of asteroids circle the Sun in a space between Mars and Jupiter.

- This is the debris left over from the formation of the solar system.

AsteroidsAsteroids: Come in all shapes & sizes.

Some known asteroids

- Dactyl (1.6 x 1.2 km)

- Mathilde (66 x 48 x 44 km)

Asteroid & Comet Impacts

Occasionally asteroids or comets hit the Earth.

When they do, they make enormous craters and dramatically change the environment.

Be a Prize winner!

“Can anyone name or describe an asteroid strike that hit Earth?”

Be a winner...Earn a prize for your answer.

Be a Prize winner!

“Can anyone name or describe an asteroid strike that hit Earth?”

We believe that the dinosaurs became extinct after either a large asteroid or comet hit the Earth just off the Yucatan Peninsula 66 million years ago.

Any other answers?

Natural & Man-made Space Objects

There are 2 types of space objects that surround us and from time to time impact our planet;

- natural objects (comets, asteroids & meteoroids) that originate from the formation of our solar system

- man-made objects that have been filling up the sky since Octber 4, 1957 when the first satellite was launched into space

Man-made Space ObjectsMan-made space debris:

Orbits the Earth in a giant cloud...

• out of use satellites • used launch vehicles

(rockets) • pieces of broken metal

and plastic

Man-made Space ObjectsSpace debris:

- Objects do not pose a great threat to the Earth.

- Burn up in fiery balls as they descend to Earth and pass through our atmosphere

Man-made Space ObjectsSpace debris:

- Its becoming a problem as we launch more satellites on missions into space

- In 2009, satellite, Cosmos 2251, collided with another satellite, Iridium 33

Be a Prize winner!

“Who can name the largest man-made satellite ever to

orbit the Earth?”

Come up with an answer and win a prize...

Be a Prize winner!“Who can name the largest man-made satellite to orbit the Earth?”

The International Space Station

- The International Space Station (ISS) is a habitable artificial satellite in low Earth orbit.

- Its first component was launched into orbit in 1998; the last pressurised module was launched and fitted in 2011.

- The station is expected to operate until 2028.

Meteoroids, Meteors (Shooting Stars) & Meteor Showers

We now leave the world of large natural and man-made objects

...and re-enter the world of meteoroids, meteors (shooting stars) and meteor showers

...the world of Perseids

Meteoroids

- A shooting star begins life in outer space.

- When its sitting out in space we call it a meteoroid

Meteors or Shooting Stars

As we orbit through space meteoroids are attracted by the Earth’s gravity.

Pulled towards the Earth meteoroids enter the Earth’s atmosphere travelling at 30 kilometers per second.

Meteoroid Meteor

The meteoroid will change its name as it speeds towards the Earth.

Meteors or Shooting Stars

- As the travelling meteoroid penetrates the Earth’s atmosphere, it starts to burn up.

- We then call it a meteor or shooting star.

Meteorites- If the meteor does not entirely burn up, at the end of its journey it may be the size of a pebble or grain of sand.

- We call these objects meteorites.

A meteorite originally formed over 7 billion years ago ...nearly as old as our solar system.

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Meteorites & Space Dust

About 20 million particles of space dust fall to the Earth every year

...that’s about

Meteor Showers- Can observe shooting stars all year long.

- There are periods during the year when there is a high concentration of shooting stars.

- We call these meteor showers

-During these periods you can see between 60 and 100 shooting stars each hour

.....if there is no moon and the light pollution is low.

Meteor Showers“Why does The Perseids meteor shower occur?”

- There is a stream of debris called the Perseid cloud. It stretches along the orbit of the Swift–Tuttle comet. The cloud consists of particles ejected by the comet as it travels on its orbit around the Sun.

- The Perseid shower is

►►visible from mid-July...the peak in activity August 9 to 14, when the Earth’s orbit intersects the Perseid cloud.

Meteor Showers .

Meteor Showers

“Why is it named The Perseids?”

It’s called The Perseids because the point in the sky where the shower appears to originate, lies near the constellation Perseus.

Meteor ShowersHere’s a list of important meteor showers:

• The Perseid – August 11 to 13 (associated with Swift-Tuttle comet)

• The Orionid – Oct 20 to 22 (associated with Halley’s comet)

• Geminid - Dec 13 to 15 (associated with 3200 Phaethon, thought to be a Palladian asteroid)

The Perseid Meteor ShowerThe Perseids meteor shower is the most popular.

“Why?”...Because the conditions are very favourable for viewing.

• It’s the middle of the summer • People are on vacation • We tend to be in the country where there is low light pollution • It’s comfortable to sit outside and view “the show”

The Perseid Meteor Shower

The Orionid Meteor Shower

October 20 - 22

The Geminid Meteor Shower

December 13 – 15

Be a Prize winner!

“Why do the Perseids occur at about the same time every year ?”

Figure out the answer and win a prize...

The Perseid Meteor ShowerBe a Prize winner!

“Why do the Perseids occur at about the same time every year ?”

1) The Earth is like a huge ship sailing through the solar system in the same orbit around the Sun every year.

2) Like Earth, Halley’s Comet has a regular and undeviating orbit around the sun. It leaves particles in its wake which the Earth sails through at the same time every year.

Things You Need to do to View a Meteor Shower

- A flashlight so you don’t fall or stumble in the dark

- Some music so you can create a contemplative and relaxing mood for your stargazing, or to listen to the meteor.

PLUS

Viewing Meteor Showers- Relax in a comfortable reclining chair.

- Get together with friends or a group of people interested in astronomy.

- Be patient…wait for the show to begin.

Viewing Meteor ShowersCheck the weather forecast and make sure to plan your stargazing when there is a clear night sky.

Listening to a Meteor- A meteoroid vaporizes as it passes through the atmosphere, and briefly ionizes air molecules along its path.

- Forming a cylinder several miles or more in length, this trail of ions can reflect radio waves.

- The ion trails disperse rapidly, and the reflected radio waves last for only a few seconds.  

Listening to a Meteor“How do you listen to a meteor?”

- On the FM dial, go to the 88 MHz band and tune into the faint signal of a faraway radio station.

“What are you listening for?”

- You’ll hear a hiss of noise when you're tuned in to an "empty" radio frequency... - BUT as meteors zip in through the atmosphere, a silent station will abruptly "boom in" for a second or two...you might also hear a "pop" or whistle.

How to capture space dust from a meteor shower.

Capturing your space dust

Put a bucket of water outside during the time of the meteor shower.

Capturing your space dust

Half fill the bucket and leave it outside for several days

Capturing your space dust

After a few days delicately empty most of the water in the bucket…Make sure you leave an inch in the bottom.

Capturing your space dust

Let the remaining water evaporate in the sun.

Capturing your space dust

Once the bucket is dry, carefully brush the particles that remain in the bottom of the bucket onto a piece of white paper.

Capturing your space dust1) Place a mirror under the paper that has your space dust.

2) Then place another piece of paper on top of the one that has your space dust,

3) Place a magnet on top of the upper piece of paper. The magnet will attract the metallic space dust to the bottom of the upper sheet.

4) Carefully slide away the bottom sheet.

5) Remove the magnet.

6) The space dust will fall onto the surface of the mirror.

Capturing your space dust

Using a magnifying glass, examine your space dust.

Your Final Chance to be a BIG WINNER

Based on what you heard tonight, how many meteors per hour would you expect to see during a Perseids meteor shower?

Meteor ShowersHere’s the answer...

- During these periods you can see between 60 and 100 shooting stars each hour...if there is no moon and the light pollution is low.

Meteor Showers

Thank you for your visit.

We’d love to see you again.