Category The Universe, Exploring the Universe, Solar System, The Moon, Space, Space Travel

Which is the outer part of the sun’s atmosphere, at hundreds of degrees higher temperature than the surface?

Our Sun is surrounded by a jacket of gases called an atmosphere. The corona is the outermost part of the Sun’s atmosphere.

The corona is usually hidden by the bright light of the Sun’s surface. That makes it difficult to see without using special instruments. However, the corona can be seen during a total solar eclipse.

The corona reaches extremely high temperatures. However, the corona is very dim. Why? The corona is about 10 million times less dense than the Sun’s surface. This low density makes the corona much less bright than the surface of the Sun.

The corona’s high temperatures are a bit of a mystery. Imagine that you’re sitting next to a campfire. It’s nice and warm. But when you walk away from the fire, you feel cooler. This is the opposite of what seems to happen on the Sun.

Astronomers have been trying to solve this mystery for a long time. The corona is in the outer layer of the Sun’s atmosphere—far from its surface. Yet the corona is hundreds of times hotter than the Sun’s surface.

A NASA mission called IRIS may have provided one possible answer. The mission discovered packets of very hot material called “heat bombs” that travel from the Sun into the corona. In the corona, the heat bombs explode and release their energy as heat. But astronomers think that this is only one of many ways in which the corona is heated.

 

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What is your weight on the Moon?

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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Why can’t you take Coca-Cola into space?

We have tested Coca-Cola (and Pepsi) in space. In 1985, we flew special dispensers from the manufacturers as an experiment aboard the Space Shuttle.

Soda in space is a bit problematic. In micro-gravity, the light gas bubbles won’t rush to the top of the liquid and escape. They will stay within the liquid. This means the astronaut will consume significantly more gas drinking a soda in space than one would drinking a soda on the ground. Drinking a carbonated beverage could be like drinking a foamy slurp.

That means there will be more of a need to burp, to release that gas. That would be okay, except burping in space is unpleasant, for the same reason mentioned above for the soda. On the ground, gases and liquids naturally separate in the digestive system because the lighter gases rise above the heavier liquids. But, in micro-gravity, that doesn’t happen. When one burps in space, it is often a “wet burp” which means some liquid is expelled. It’s kind of like acid reflux.

 

Credit : Quora

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What will happen if an astronaut fires a gun from the Moon aiming at Earth?

The .220 Swift remains the fastest commercial cartridge in the world, with a published velocity of 4,665 ft/s (1,422 m/s) and the escape velocity of the MOON is 2,400 m/s so the bullet will not leave the vicinity of the Moon and will eventually return to the surface.

And to respond to the dozen’s of people who have commented below that a rifle bullet will not work in space or on the Moon , yes it will , and actually , like a rocket it will work marginally better . A bullet carries it’s own oxygen in it’s propellant powder and does not need air to ignite !

The only ballistic (Non missile) round that would leave the moon would be one coming from a rail gun which can reach a velocity of upwards 5–6000 m/s (21,600 km hr).

If aimed very accurately which would be very difficult to do it could enter the earth’s atmosphere at a speed in excess of 40,000 km/h or 11,100 m/s .

As the projectile enters the Earth’s atmosphere it will compress the air ahead of it to a temperature of 8000–10,000ºC and melt and burn up , not striking the ground but vaporizing 15 -20 kilometers above ground maybe terminating in a loud explosion.

 

Credit : Quora

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How do space telescopes keep their lenses clean?

They don’t get dirty.

There is nothing in the vacuum of space to collect on the mirror.

Orbital debris is a potential problem, but experience with Hubble shows that it’s not too serious. But if the mirror does get hit, it’s not something you’ll be able to clean off…it’ll be a hole the size of a quarter.

Hubble’s biggest problems with debris has been impacts to its solar panels:

But Hubble is in a moderately low orbit – because that’s as high as the crappy Space Shuttle could get it.

These days, we’d put it MUCH farther from the Earth—far from the places where debris is common.

The James Webb Space telescope isn’t even going to be orbiting the Earth—it’s going to be parked in a Sun-centered orbit at the Earth/Sun L2 point.

 

Credit : Quora

Picture Credit : Google

If an astronaut fell over a 300 ft cliff on The Moon, would the low gravity save him, and would he bounce?

It’s not the fall that kills you, it’s the sudden stop at the bottom.

Bouncing doesn’t come into it. The question is, how fast are you going when you hit something. The faster you are going, the more energy you contain when you hit the ground—energy that now tries to break bones and crush organs like tomatoes on the windscreen of a passing car.

On Earth, the general rule of thumb is that you risk serious injury from any fall higher than you are. On the moon that would have to be adjusted; lunar gravity is only 1/6th as strong, but there is no air—so you will never reach a “terminal velocity” beyond which you don’t speed up any further.

If an astronaut fell 300 feet on the moon, that’s a 91.44 meter drop at 1.633 meters per second per second acceleration (we’ll do this in metric because metric isn’t a stupid, byzantine measuring system). With no air resistance at all, our hapless astronaut will hit the ground after 10.6 seconds, at a velocity of 17.2 meters per second.

How dangerous is that? Well on Earth, to hit the ground at 17.2 meters per second (ignoring air resistance), you’d have to fall from a height of 15.2 meters, or 49.8 feet, or the roof of a five story building. Onto rock or dry sand. Does that sound like a good idea?

No. Such a drop would likely break the spacesuit and would certainly break the occupant.

 

Credit : Quora

Picture Credit : Google