My Science School

In the event of a total solar eclipse, the Sun’s light is completely blocked by the Moon. But have you wondered how the Moon, which is about 400 times smaller than the Sun, can block the light from the big star?

It’s a matter of distance

The distance between the Earth and the Sun, and the Earth and the Moon is at the crux of this answer.

Objects that are closer to us appear much larger than objects that are much farther away. For example, the stars in the sky might look like tiny objects but are actually much larger than the Sun. they appear so because their distance from the Earth is much more than the Sun’s distance from Earth.

Thus, though the Moon is 400 times smaller than the Sun, because it is much closer to Earth, it appears to be the same size as the Sun from Earth. So, when the Moon comes between the Earth and the Sun, it appears to completely block the light from the Sun.

An end to total eclipse?

Total solar eclipses won’t be around forever because the Moon’s orbit is changing. The Moon’s orbit grows about 1.5 inches larger every year. And as the Moon’s orbit takes it farther away from the Earth, it will appear much smaller than it does currently. Once the Moon’s growing orbit takes it approximately 23,500 km farther from Earth, it will be too far away to completely block the light from the Sun.

The good news though is, if you look at the maths, this won’t happen for the next 600 million years, at least.

 

Picture Credit : Google

Astronauts Neil Armstrong and Edwin (Buzz) Aldrin were the first humans to step foot on the Moon on July 20, 1969, and naturally, they left behind their footprints.

But do these still exist? Yes, they do!

How long will they last?

The first footprints, rather, all the footprints left on the Moon between 1969 and 1972, when the last human mission to the Moon happened, will still be there.

They might actually be there for years and years together, and if we are lucky, probably as long as the Moon lasts.

Why?

This is because unlike Earth, there is no erosion by water or wind on the Moon as it has no atmosphere and all the water on its surface is frozen. Also, there is no volcanic activity on the Moon which can change the lunar features. So, nothing really gets washed away from the Moon’s surface.

It may or may not last forever

The reason there is no guarantee that the footprints will remain permanently on the Moon is because of meteorites and solar wind.

Like the planets and other objects in the solar system, the Moon too is prone to bombardment by meteorites. Even one little space rock that lands anywhere near any of the footprints can wipe them off.

Due to the lack of atmosphere on the Moon, it is exposed to solar wind, which is a stream of charged particles coming from the Sun. Over time, this solar wind can act like the weather on Earth and scour the surface of the Moon, wiping away all footprints.

The good news though is that this process is very, very slow. So, footprints on the Moon are likely to remain there for a really long time.

 

Picture Credit : Google

For those living near the North or South Pole, the night sky can often put on a show, dubbed the aurora. The lights are called aurora borealis or northern lights near the North Pole, while it is called aurora australis or southern lights near the South Pole.

Irrespective of where it occurs, it is quite a sight to behold. And even though the spectacle is best seen in the night, it is actually caused by the sun.

When the sun burps…

Along with heat and light, sun sends a lot of energy and small particles as well. While the Earth’s magnetic field is adept at shielding us from these most times, there are occasions when the energy and small particles can travel into the Earth’s atmosphere, especially near the poles.

One of those occasions occurs during a coronal mass ejection, a type of a solar storm. The sun can be said to burp a huge bubble of electrified gas that has ability to move at high speeds through space. Some of the energy and solar particles from this can make their way to the Earth’s atmosphere near the poles.

Not just on Earth

Once in the Earth’s atmosphere, the particles can then interact with the gases available. It is this interaction that results in the brilliant displays in the night sky. Green (like in the picture here) and red lights are given off by oxygen, while interaction with nitrogen leads to a bluish or purple glow.

Auroras are not limited to just Earth. If a planet possesses an atmosphere and magnetic field, then the chances of auroras open up. In fact, we have observed splendid auroras both on Jupiter and Saturn. 

 

Picture Credit : Google

While we experience Earth's many weather conditions each year, let's see how the weather is on the remaining seven planets.

Mercury

Due to its closeness to the Sun the planet goes through extreme temperatures. In the

daytime, the Sun appears three times larger and over 10 times brighter than on Earth. This pushes temperatures to nearly 800 degrees Fahrenheit. And since there is no atmosphere in Mercury, the daytime heat cannot be trapped. Hence, temperatures can drop as low as 300 degrees Fahrenheit during night time

Venus

While Venus is farther away from the Sun than Mercury, it is the hottest planet in the solar system. This is because Venus is covered by a thick atmosphere of carbon dioxide and clouds made of sulphuric acid. Together, these act like a greenhouse, trapping heat and warming the planet. On average, temperature on Venus can reach as high as 847 degrees Fahrenheit

Mars

Mars weather is the closest to Earth's. Daytime temperatures on the planet can be close to Winter temperatures on Earth, reaching as high as 32 degrees Fahrenheit. However since it has a thin atmosphere, night temperatures can be as low as -200 degrees Fahrenheit

Jupiter

Since it is far away from the Sun, the planet is only slightly heated up by the star. Jupiter gets most of its heat from the inside of the planet. The temperature of the planet varies in the layers of Jupiter's atmosphere. On average, Jupiter's temperature is -234 degrees Fahrenheit.

However, closer to its core, the temperature can go up to 43,000 degrees Fahrenheit!

Saturn

Saturn is really far away from the Sun about 1.4 billion km away Hence, the planet has relatively freezing temperatures throughout which averages at -285 degrees Fahrenheit.

Uranus

The planet is known as an ice giant, and truly so. Is temperature is about 360 degrees Fahrenheit. Due to Uranus being tilted on its own axis, it also experiences different seasons like Earth.

Neptune

Neptune is the farthest planet in the solar system. It is about 3.7 billion km away from the Sun. While that would make it a freezing planet, its temperature is the same as Uranus (-360 degrees Fahrenheit). It is still a mystery to scientists as to why this is so.

 

Picture Credit : Google