My Science School

For many years, scientists believed that Jupiter's moon lo was geologically dead. This means it didn't have things such as earthquakes, newly forming mountains or volcanoes. However, it turns out the scientists were wrong about lo. In 1979, when NASA's Voyager 1 spacecraft took close up pictures of lo, the pictures showed a massive plume erupting from lo's surface into space. That's when they realise that lo did not just have volcanoes, it had active volcanoes. And, lo was no longer considered geologically dead. When these pictures were taken it was the first time an erupting volcano was found anywhere other than Earth. So that leaves us wondering, do all the planets and their moons have active volcanoes? Let's take a look

Mercury: The planet once had active volcanoes, but not anymore. Scientists believe violent volcanic eruptions that shaped Mercury's surface, likely ended about 3.5 billion years ago.

Venus: Venus, on the other hand is covered with volcanoes. The hottest planet in our solar system has over 1,000 volcanoes, including some that might still be active, according to what scientists think.

Mars: Mars is home to Olympus Mons, the solar largest volcano in our system. It is also the mountain in our solar largest led our solar system Mars is filled with tall volcanic mountains, and while scientists haven't seen an eruption on Mars, they think there could be some in the future.

Jupiter: Scientists have found volcanoes and observed volcanic activity only on lo, Jupiter’s moon. Eruptions from lo's volcanoes are so massive that it can been seen by a spacecraft that is pretty far from lo.

Saturn: Saturn's moon Enceladus has cryovolcanoes. These volcanoes are similar to regular volcanoes, except they spew water and other gases like geysers.

Uranus: Since it is a gas planet, it does not have any volcanoes.

Neptune: While Neptune doesn't have volcanoes as it is a gas planet, its frozen moon, Triton, has cryovolcanoes that are active.

 

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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.

 

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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. 

 

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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.

 

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À nebula (plural nebulae) is a giant cloud of dust and gas in space. Most nebulae are formed from the gas and dust thrown out by the explosion of a dying star, while some are formed from the gas that is already in the interstellar medium (the matter and radiation that exist in the space between the star systems in a galaxy).

Where are the nebulae?

Nebulae exist in interstellar space. Astronomers use very powerful telescopes to take pictures of faraway nebulae. Many of NASA's space telescopes such as the Spitzer Space Telescope and Hubble Space Telescope have captured many images of faraway nebulae. The closest known nebula to Earth is called the Helix Nebula, the remnant of a dying star, possibly one like the Sun. The Helix Nebula is approximately 700 light years from Earth. This means it will take 700 years to reach this nebula if one travels at the speed of light.

Star nurseries

Some nebulae are regions where new stars are beginning to form. This is why they are called 'star nurseries'. A nebula is made of dust and gases, mostly hydrogen and helium. These dust and gases are very spread out. However, gravity can slowly pull together clumps of these dust and gas. As each clump gets bigger in size, its gravity gets stronger. Eventually, the clump gets so big that it collapses from its own gravity. This collapse causes the material at the centre of the cloud to heat up. It is this hot core that is the beginning of a star.

 

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Sometimes, you may have watched the moon near the horizon and wondered "Why is the moon unusually bigger tonight?" Does the moon grow bigger near the horizon and shrink when it moves high up in the sky? This perception is called Moon illusion: Your brain is playing a trick on you.

Sky watchers have observed this phenomenon for thousands of years. The precise reason for the moon appearing to be expanding and contracting continues to puzzle scientists even today. But in general, our brain is tuned to think that objects near the horizon are (usually) more distant and larger than those overhead. But one thing is for sure - the moon isn't changing size.

Here is an activity to test this: Take a sheet of paper and roll it up into a narrow tube. Point it at the rising moon, look through it and adjust the tube's size until it's slightly larger than the moon. Fix the tube using a tape so its size stays the same and look at the moon again a few hours later when it's higher in the sky. You'll see it fills the same space.

 

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A galaxy is a huge collection of stars, their solar systems, dust and gas. It is held together by gravity.

Earth is a part of the solar system, which is a small part of the Milky Way Galaxy. All those stars you see in the sky at night belong to the Milky Way.

When you are far away from city lights, some place really dark, you can even see the dusty bands of the Milky Way stretch across the sky.

How many are there?

There are countless galaxies out there. Once, when the Hubble-Space Telescope looked at a small patch of space for 12 days. It found nearly 10,000 galaxies of all sizes, shapes and colours.

Some scientists believe there could be as many as one billion galaxies in this universe!

How do they look?

Galaxies came in different shapes. But the two most common types, based on ones discovered so far, are Spiral Galaxy and Elliptical Galaxy.

The Milky Way is a spiral-shaped galaxy. This type of galaxy has curved arms that make it look like a pinwheel.

Elliptical galaxies, on the other hand, are smooth, and oval shaped.

Just like ours, other galaxies too get their light from stars that inhabit them.

On collision course

There are times when two or more galaxies can get too close and smash into each other. For example, the Milky Way galaxy will someday bump into the Andromeda galaxy, its closest neighbour.

However, this won’t happen for another five billion years at least, and even if it were to happen anytime soon, you wouldn’t notice and spread out at the ends that even if they do bump into each other, the planets and solar systems often don’t get close to colliding.

 

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Scientists send spacecraft to probe objects in space. These spacecraft carry instruments that help them take pictures and collect data in space and send them back to Earth. But to do this, the spacecraft needs electricity So what powers it?

Based on the mission it is assigned, and factors such as where the spacecraft is travelling, what it plans to do there and how long it needs to work engineers choose the best way to power a spacecraft.

The Sun

One source of power engineers consider is energy from the Sun, or solar power. Spacecraft that orbit close to Earth are dose enough to the Sun to use solar power. These spacecraft are fitted with solar panels, which convert the Sun's energy into electricity. The electricity from the panels charges a battery in the spacecraft and can be used even when the spacecraft doesn't have direct sunlight

Batteries

Sometimes, when the mission is only for a short duration, such as the Huygens probe that landed on Titan, Saturn's largest moon, and meant to work only for a few hours, engineers may power the spacecraft with batteries. These batteries are designed to be tough since they need to withstand the harsh environment of space.

Atoms

An atom is a tiny building block of matter. Atoms need to store a lot of energy to hold themselves together. However, atoms such as radioisotopes are unstable and begin to fall apart. As they fall apart, they release energy as heat. A radioisotope power system uses the temperature difference between the heat from the unstable atoms and the cold of space to produce electricity. This system produces power for a very long time even in harsh environments. That's why this system has been used to power many of NASA's missions, including the two Voyager spacecraft that continue to send back information after over four decades in space.

 

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Chinese space probe Chang'e- 5, carrying rocks and soil from the Moon, returned to Earth safely on December 17. The capsule carrying the samples landed in northern China's Inner Mongolia region. This is the first lunar sample return since 1976, when the former Soviet Union's Luna 24 returned with lunar material. What's the current mission all about? What happened to the Moon rocks that were recovered by the U.S. and Russia?

What is Chang'e-5 mission about?

Chang'e-5 is a robotic mission of the Chinese Lunar Exploration Program, launched on November 23, 2020. The Chang'e 5 probe included a lander, an ascender, orbiter and a returner. After it entered the designated circular lunar orbit, the lander-ascender pair separated from the orbiter-returner group and descended and successfully touched down near Mons Rumker, a volcanic mountain in the Moon's huge Oceanus Procellarum ("Ocean of Storms") region on December 1, 2020. The mission spent only two days on the Moon's surface, gathering samples by digging and scooping. The 2kg samples were loaded onto an ascent vehicle that subsequently docked with an Earth return module. The service module of the mission's orbiter then released the return capsule, which eventually landed on Earth with the samples on December 17.

What is the significance of the landing site?

• The landing site is a volcanic plain called Mons Rumker in the Oceanus Procellarum region on the Moon's near side. The places explored by Apollo and Luna were all more than 3 billion years old, whereas Mons Rumker is estimated to be around 1.2 billion years old.


• A young surface is smooth and almost unblemished, while an old surface is heavily cratered With Moon rocks collected by Neil Armstrong and other astronauts, scientists could measure radioactive elements in the rocks and precisely calculate when a volcanic eruption had occurred, and thus the age of the parts of the Moon where the Apollo explorers set foot But none of the previous missions landed on a younger part of the Moon, leaving a large gap of uncertainty.


• Scientists also want to understand the differences in composition of the varying parts of the Moon, and the samples might explain how part of the Moon was still molten some 3 billion years after it formed.

How will the samples help scientists understand the Moon?

The new specimens could provide fresh insights into the geology and early history of Earth's natural satellite. Scientists hope the samples will help them learn about the Moon's origins, formation and volcanic activity on its surface. China will make some of the samples available to scientists in other countries.

Where are the Moon rocks previously collected by the U.S. and Russia now?

In the 1970s, three successful Soviet Luna missions brought back a total of 301 grams of Moon samples. NASA's Apollo astronauts lugged back 842 pounds of Moon rock and soil Scientists are still studying the Apollo and Luna samples.

• The Moon samples collected by Apollo astronauts are stored at the Lunar Sample Laboratory Facility at NASA's Johnson Space Center in Houston, Texas, in nitrogen filled steel cabinets. Some of those collected by Luna missions had been auctioned.


• In 2000, the U.S. decided to give away Moon rocks to 32 Apollo astronauts, on the condition that they should not be sold.


• Moon rocks collected by Apollo 11 and Apollo 17 astronauts were given away to 135 countries around the world and the 50 U.S. states as a token of goodwill.

What are China's other moon missions?

In this century so far, only China has successfully put robotic spacecraft on the surface of the Moon: Chang’e-3 in December 2013, and Chang’e-4 in January 2019 became the first spacecraft to land on the far side of the Moon Chang’e-4 is still roving and studying lunar geology. Chang’e-1 and Chang’e-2 were lunar orbiters, launched in 2007 art 2010 respectively. All the missions have been named after the Chinese Moon goddess, Chang’e.

What are China's upcoming Moon missions?

China plans to launch a spacecraft called Change 6 to return samples from the Moon's South pole. The more advanced Chang'e 7 and Chang'e-8 spacecraft are also slated to land near tire south pole to carry out analysis of the region and test new technologies, including detecting and extracting materials such as water and hydrogen that could be useful to future human explorers, and testing 3D printing on the lunar surface China hopes to launch an international Lunar research station and ultimately a human colony on the Moon by the 2030.

 

Picture Credit : Google

When one object crosses in front of another in space, it is known as transit. For example, when the Moon passes between the Earth and the Sun, the Moon is ‘transiting‘ the Sun.

Why is it important?

Just like objects in our solar system that transit the Sun, there are objects outside our solar system too that transit stars there. These objects include planets known as explants, and their transit help scientists identify these planets.

If the orbit of a planet is lined up right, the planet is lined up right, the planet will transit the star it orbits. When this happens, the light from the star dims by a small amount of time between each transit. This is how scientists discovered seven exoplanets around a star called TRAPPIST-1. There of these planets were discovered in 2015, while four more were identified in 2017.

Bottomline, transits not only help scientists identify new planets but also understand the world beyond our solar system.

The transits we can see

From Earth, there are two main transits that can be seen by people. One is the transit of the Moon, as it passes the Sun. this is when we witness a solar eclipse. The other is the transit of the planet Venus when it passes between the Earth and the Sun during its orbit.

While solar eclipse can be observed often, the transit of Venus cannot be seen frequently because of how he orbits of Venus and Earth are lined up. The last transit of Venus was on June 6, 2012. The next one, however is not until 2117!

 

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For a planet to be habitable for humans, 1) it should be at a safe distance from the Sun - should be neither too hot, nor too cold; 2) it should contain liquid water, and 3) it should have a protective atmosphere that keeps the Sun's radiation out. There is only one planet in the solar system that satisfies all these conditions and that planet is Earth. The next best option is Mars.

Mars has many advantages. It is very close to Earth - humans can reach the Red Planet in less than six months from Earth.

A Martian day is just over 24 hours long, roughly equivalent to a day on Earth. Mars has an atmosphere (though a thin one) that offers protection from cosmic radiation and solar radiation. Gravity on Mars is 38% that of Earth, which is believed by many to be sufficient for the human body to adapt to.

Evidence suggests that water may exist in the subsurface all over Mars. With help from technology, humans can survive on Mars, whereas the survival chances are slim on other planets and their moons.

 

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If last week's story on the birth of the Moon fascinated you here's another quick fact about the Moon that is sure to grab your attention - your weight on the Moon would be much less compared to that on Earth! Yes, that's true. Here's why.

It all comes down to gravity

Your weight is a measure of the amount of gravity exerted on your body. Since gravity on each of the planets and space bodies is different your weight at any two places is bound to be different.

The gravity of an object is determined by its mass and size. Since the Moon is considerably smaller than Earth in mass, the gravity exerted on your body on the Moon is also much less - one-sixth that of Earth to be precise. However, even if you go to the Moon, only your weight will change, while your mass will remain the same as that on Earth. Actually, your mass anywhere in the universe is pretty much the same.

That makes your weight...

When you land on the Moon's surface, your weight would be one-sixth of your current weight here.

For example, if you weigh 60 kg on Earth, your weight on the Moon's surface would be about 10 kg.

 

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People often see animations of earth rotating on TV in the opening of news shows, sporting events and other kinds of motion graphics, but those are just animations. And they are not realistic

The fact is that even though the Earth rotates at over 1,000 miles per hour at the equator (1,037.54 mph to be exact), and slower as you go north or south. If you were out in space far enough away from the earth to see the whole planet it would appear to turn so slowly that it would appear motionless.

The picture below shows how far the Earth turns in 1 hour. For a comparison imagine you're looking at a clock. The hour hand doesn't look like it is turning, but it actually turns twice as fast as the Earth.

 

Credit : Quora

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 The one animal I found the most interesting regarding visually seeing the stars is the Dung Beetle!

Yes, would you believe the dung beetle uses the milky way for navigation?

Apparently the dung beetle is actually pretty smart. Other than playing with poop, that is. Some really unfortunate scientists got to spend some quality time with one of the most maligned creatures on the earth. But what they found was nothing short of amazing. They had known for some time that the beetle used the polarized light from the sun for navigation, but what did they do at night? They thought it could be the moon, but what about moonless nights? It turned out that they were using the milky way, which was confirmed by taking them to a planetarium. They found that the beetles used the visual cues of the milky way instead of something like the magnetic field.

They confirmed this in the field by giving the beetles cool hats like what you see here (the control group got transparent hats). The beetles with the opaque hats could not navigate.

 

Credit : Quora

Picture Credit : Google