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CELPIP Practice Reading: Reading for Information ID: #63145 Medium Northern lights: science and viewing tips

Read the following passage.

A. The northern lights, or aurora borealis, are displays of coloured light in the night sky of the northern hemisphere. In the southern hemisphere the same thing is called the southern lights, or aurora australis. Both happen near Earth's magnetic poles, and this is why northern Canada is one of the best places to see them. In the Canadian North, auroras can be seen almost every night from August to May, and they are most common around the spring and fall equinoxes. Astronauts on the International Space Station, which orbits at about the same height as the lights, see them at eye level.

B. The lights begin at the Sun, which blasts electrons and protons into space in a stream called the solar wind. Earth's magnetic field acts as an invisible shield that steers this wind around the planet, but its field lines are dragged and stretched until they snap back like an elastic band. This throws charged particles down toward Earth, where they collide with gases in the upper atmosphere. Each collision makes a tiny flash, and billions of flashes in a row make the aurora seem to dance. When the Sun is very active, the lights reach farther south: on the night of May 10 to 11, 2024, they were filmed in Boucherville, near Montreal.

C. An aurora's colour depends on which gas is hit and at what height. Most northern lights shine 100 to 300 kilometres above the ground, though some reach 600 kilometres. Green, the colour seen most often, comes from oxygen at 100 to 300 kilometres, while oxygen higher up, at 300 to 400 kilometres, glows red. A pink or dark red fringe sometimes appears along the lower edge, produced by nitrogen at around 100 kilometres. Hydrogen and helium can give blue and purple light, but these colours are hard for human eyes to see against the night sky.

D. Watching the lights needs no special equipment. They usually appear a few hours after sunset and grow stronger around midnight. Anyone watching should go far from city lights and check the aurora forecast and the local weather, since clouds, snow or rain and a full Moon all make the lights hard to see. Summer trips to the far north seldom work, because the sky there does not get dark in summer. Those who cannot travel can watch AuroraMAX, a camera in Yellowknife, Northwest Territories, that turns on each evening at sunset during the aurora season.

E. Not given in any of the above paragraphs.

Decide which paragraph, A to D, has the information given in each statement below. Select E if the information is not given in any of the paragraphs.

- 1.
Material thrown out by the Sun is pushed around our planet by an unseen protective barrier.

- 2.
The shade that people notice most frequently is created by oxygen.

- 3.
In the far north of the country, the display can be viewed on nearly any night for most of the year.

- 4.
The Latin name for the lights was first used by a scientist working in Canada.

- 5.
Anyone hoping to see the lights should find a dark place and look at the predictions first.

- 6.
The pinkish edge along the bottom of some displays comes from a gas other than oxygen.

- 7.
What looks like movement in the sky is really a rapid series of very small bursts of light.

- 8.
Heading north in the warm season for a viewing trip is usually a poor plan because the sky stays too bright.

- 9.
The camera in Yellowknife was put up to help airlines plan flights across the North.

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