Category Earth Science

How many watts is a lightning strike?

Lightning is a natural electrical discharge created by imbalances between a cumulonimbus cloud and the ground or within itself. Lightning is pure electricity involving small particles with positive and negative charges that pull toward each other like the north and south ends of magnets. Lightnings are scary and of course dangerous, but it is a subject of fascination for scientists. During thunderstorms, scientists  witness a lot of lightning.  On an average, scientists have mapped, there are about 100 lightnings per second worldwide.That’s a whopping number. Imagine the amount of energy that’s shooting up from the clouds. Each bolt can contain up to one billion volts of electricity. This means a single lightning flash has enough energy to light a 100-watt bulb for three months!  So, How many homes could a lightning bolt power? Every lightning bolt on Earth in one year, captured perfectly with no loss of energy, would contain about 4*10^17 joules of energy. Thus, all the lightning in the entire world could only power 8% of US households. Human body can tolerate a maximum of between 20,000 and 50,000 volts, which might prove to be lethal. In most cases, a person’s heart will stop after being struck by lightning, so the key to survival is having someone nearby who can administer CPR. Even if you survive, a lightning strike will have long-lasting effects on your body, including memory issues, muscle soreness and changes in mood.

People often confuse lightning with thunder. To put it simply, lightning is electricity; thunder is sound. In other words, lightning is the sudden flash of light spotted in the sky, while thunder is the roaring, cracking sound that is commonly heard during thunderstorms. And because light travels faster than sound, lightning is seen before thunder can be heard.

Picture Credit : Google 

WHERE IS THE ANTARCTIC CIRCLE?

The Antarctic Circle is a parallel of latitude on the Earth at approximately 66.5 degrees south of the equator. On the day of the southern summer solstice (around December 22 each year), an observer on the Antarctic Circle will see the Sun above the horizon for a full 24 hours.

Observers further south than the Antarctic Circle will see the Sun remain above the horizon for many days, and at the South Pole, there is a six-month ‘day’ that starts on the autumnal equinox changing to a six-month ‘night’ on the vernal equinox.

The 66.5 degree angle comes from the tilt of the Earth’s rotation axis (23.5°), such that 90° – 23.5° = 66.

Credit: Cosmos

Picture credit: Google

WHAT MAKES THE SEASONS?

Earth is always tilted the same direction as it orbits the Sun. So when Earth is on one side of the Sun, the northern hemisphere is tilted closer towards the Sun, making it warmer. At the same time, the southern hemisphere is tilted away from the Sun, and is, therefore, colder. When Earth reaches the other side of the Sun, it is the opposite, so it’s winter in the northern hemisphere and summer in the southern.

Seasons happen at different times in different parts of the world. The tilt of the Earth doesn’t change as it rotates around the Sun. But the part of the planet that gets the most direct sunlight does change.

The Northern Hemisphere is tilted away from the Sun from September to March. That means the northern half of the planet doesn’t get as much light and heat from the Sun. This causes autumn and winter. During the same months, the Southern Hemisphere is tilted towards the Sun. That means the southern half of the planet gets spring and summer.

From March to September, the Northern Hemisphere is tilted towards the Sun. So that’s when the northern half of the Earth experiences spring and summer. During the same months, the Southern Hemisphere experiences autumn and winter.
Other planets also have seasons. But the length and intensity of each season varies from planet to planet.

  • On Earth, seasons last between 90 and 93 days.
  • On Venus, seasons last between 55 and 58 days.
  • On Mars, seasons change about once every six months. Summer lasts 199 days and winter lasts 146 days.
  • On Saturn, seasons last about seven years.
  • And if you lived on Neptune, you would have to wait more than 40 years for the seasons to change!

Credit: Let’s talk Science

Picture credit: Google