What’s beyond the Milky Way?



All the stars you can see at night belong to our galaxy, the Milky Way. To get a grasp of the size of the Milky Way, let's consider the time for light to travel from one place to another. It takes about one second for light to reach us from the surface of the Moon, eight minutes from the Sun, and four years from the nearest other star. But from the edges of the Milky Way, light takes tens of thousands of years! And despite its vastness, the Milky Way is just one galaxy amongst billions of other galaxies scattered in the immensity of the universe.



Our closest neighbours are small galaxies orbiting the Milky Way. Beyond them, the Andromeda Galaxy is bigger than the Milky Way. The Milky Way will eventually collide with it. For the moment though, its light takes more than two million years to reach us. Even farther away lies the Virgo duster, which comprises more than a thousand galaxies. But this is still the neighbourhood of our Milky Way. The farthest galaxy ever observed is so far it takes light 13 billion years to reach us. Wherever telescopes look, they spot thousands and thousands of galaxies!



 



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How do astronauts write in space?



Legend has it that during the height of the space race in the 1960s, NASA scientists figured that pens could not function in space. So, they spent millions of dollars developing a pen that could write in space, while their Soviet counterparts used the humble pencil.



This story has been floating around the Internet for way too long. However, it is just a myth.



The truth



According to NASA historians, NASA astronauts also used pencils. In 1965, NASA ordered 34 mechanical pencils from Houston's Tycam Engineering Manufacturing, Inc. at the rate of $ 128.89 per pencil. When the public got to know about these rates, there was an outcry, and NASA had to find something much cheaper for its astronauts to use.



The pencil loses out



The pencil wasn't an ideal choice for writing in space because its tip could flake and break off, drifting in microgravity with the potential to harm an astronaut or an equipment. Apart from this, pencils are flammable, and NASA wanted to avoid anything flammable aboard a spacecraft.



And the pen?



Regular pens that work on Earth did not work in space because they rely on gravity for the flow of ink to the nib. This was understood quite early by scientists and hence astronauts used pencils. But with both the pencil and the pen creating issues, what did NASA finally resort to?



The saviour



Around the time NASA was embroiled in the mechanical pencils controversy, Paul C. Fisher of the Fisher Pen Co. designed a ballpoint pen that could work in space. His company invested one million dollars to fund, design, and patent the pen on its own.



Fisher's pen operated seamlessly, not just in space, but also in a weightless environment, underwater, in other liquids, and in temperatures ranging from -50 F to +400 F.



The company offered the pen to NASA, but the space agency was hesitant to buy it due to the mechanical pencil controversy.



However, a few years later, after rigorous testing, NASA agreed to equip its astronauts with the space pen. The space agency bought 400 pens from Fisher. And a year later, the Russians also ordered 100 pens and 1,000 ink cartridges to use on their Soyuz space missions. Both NASA and the Soviet space agency received a 40 % discount on bulk purchase of the pens, paying about $ 2.39 per pen.



Over the years, Fisher's company has created different space pens, which are still used by NASA and the Soviet space agency.



If you would like to get your hands on one of these space pens, it would cost you approximately $ 50.



 



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Why do astronauts become weightless in space?



The idea of floating about completely weightless sounds great fun, but try to imagine what it must be like to lose normal control of your body. Astronauts have to learn to live in these conditions, sometimes for months on end, because when they are in space their bodies become apparently weightless. Once a spacecraft is in orbit around the earth, it remains held in position by the earth's gravity. The astronauts inside are moved by the same force, and since they and the spacecraft are moving in the same way, they are not drawn down to the floor but float about.



There is one curious side-effect of weightlessness which is encouraging to anyone who would like to be a little taller. Because their bodies are not pulled down to earth by the force of its gravity, astronauts find that they stretch a little in space. The effect does not last for long once they return to earth. Gravity soon pulls them back to their original height.



 



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Why is the moon covered with craters?



Pictures of the moon’s surface show that it is pockmarked with round walled shapes known as craters. What caused them is a bit of a mystery. Men have landed on the moon several times. A lot of satellites have been sent to look at it. Yet scientists still cannot say for certain what caused the craters. The moon does not have an atmosphere like the earths. This makes it easier for meteorites to smash into its surface. Meteorites heading towards earth often break up as they pass through the atmosphere. So meteorites probably caused a good many of the moon’s craters.



A lot of the craters are huge. Some measure over 150 kilometres across. Others are so tiny they cannot be seen from earth. So another theory is that some craters may have been formed by volcanic activity bubbling up from inside the moon.



Most likely both meteorites and internal eruptions were responsible. But we still do not know for certain.



 



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How do space scientists make sure that their rockets land on the moon?



It may sound silly, but imagine what would happen if a rocket sent up to the moon missed its target. The moon may be pretty big. But so in space. Missing something even as big as that could easily happen, without careful control of the spacecraft. That’s why each moon shot takes months of planning and complicated calculations.



The rocket must be programmed so that soon after take-off it reaches almost 42,000 kilometres per hour. This is the speed necessary for it to break free of the earth’s gravity. After that, its speed has to be carefully controlled so that when it reaches the moon it will be travelling at about 1250 kilometres per hour.



Of course, while a rocket is flying to the moon, the moon is on the move as well. It is whizzing round the earth at an average speed of 3836 kilometres per hour. Just to complicate things further, it does not stick to a regular path. The distance between the earth and the moon can vary by as much as 52,800 kilometres! The flight controllers have to work out where the moon is going to be all through the flight, to be certain that the rocket reaches the right place at the right time. Then there is the moon’s gravity to be taken into consideration. The closer a rocket gets to the moon, the more it is affected by this gravitational pull. So for the last 3000 kilometres the scientists have to watch the rocket’s speed very closely as it becomes more and more affected by the moon’s gravity.



You can see that controlling the speed and navigation of a spacecraft is anything but easy. The speed has only got to be a couple of kilometres an hour either side of the right speed to miss the moon completely. And one degree off course could throw the rocket’s timing out by as much as seven hours.



 



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What would happen to an astronaut if he/she were to be lost in space without a spacesuit?



We know that astronauts and cosmonauts travel to space in spacecraft and require a spacesuit when they venture out of the spacecraft. An astronaut's spacesuit creates a pressurised, oxygenated atmosphere to help the astronaut breathe. It also protects the astronaut from ultraviolet rays and extreme temperatures in space. But what would happen to an astronaut if she were to be lost in space without a spacesuit?



Time in hand - not much



The astronaut will not die immediately on being exposed in space. She will have close to 15 seconds before she loses consciousness and another two to three minutes before death comes knocking. Before the two minute mark if she is pulled in by someone from the spacecraft, she does have chances of survival but her body would have gone through quite a bit.



The top cause



Not zero pressure - It is assumed that one would explode in space without a spacesuit due to zero pressure. However, this is not true. The skin is gas-tight and is strong enough to withstand any kind of pressure. Not inflation - While the body won't explode, it can still inflate due to nitrogen bubbles that would have dissolved in the bloodstream near the surface of the skin, and collected itself into little bubbles. These little bubbles will start expanding, puffing up the body, starting at the hands and feet and moving in. This is called ebullism. Ebullism can cause significant tissue damage, but it won't be the cause of death.



Not the cold - Space is really, really cold. But it will still not lead to hypothermia instantly. This is because, in a vacuum, the only way to lose heat is by radiation or by evaporation of fluid. And the human body loses heat by radiation very slowly as it is a relatively cool object. The body will eventually freeze if it is in space for too long, but there is something else that would lead to death before any of the points mentioned above. That is asphyxiation.



Yes, asphyxiation - There is no air in space, and our blood holds enough oxygen to last about 15 seconds. Post this, the brain shuts down and the astronaut will lose consciousness. If she is not pulled back in within a minute or two, all the other organs in the body will eventually shut down due to the lack of oxygen, leading to death.



Interesting fact:



Holding the breath while being exposed to the vacuum in space will cause the air in the lungs to rupture the lung tissue as it expands into the chest cavity, forcing air bubbles into the bloodstream. This can prove to be fatal even if the astronaut is rescued.



So, it important for an astronaut to not hold her breath is space.



 



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Why Jupiter is often referred to as a failed star?



Jupiter is known to us as the largest planet in our solar system and a gas giant. But did you know Jupiter is often referred to as a failed star



Not quite the mass



Jupiter is dubbed by many as a failed star because it is mostly made up of hydrogen and helium, like the Sun, but it is does not have enough mass to reach the internal pressure and temperature necessary to fuse hydrogen into helium and kickstart thermonuclear fusion. Its mass is 2.5 times that of all the other planets in the solar system combined, but it is still not enough to make Jupiter a star. The planet has only 0.1 % of the mass of the Sun.



Jupiter never had a chance



Many scientists argue that it is unfair to call Jupiter a failed star because it never had the chance to become one. Stars and planets form in different ways. A star is formed when a cloud of interstellar gas and dust collapses unto itself. Because of rotation, these clouds form flattened accretion discs that surround the central growing star. As the mass of the star grows, collecting material from the disc, the core of the star starts to squeeze and become tighter, thereby causing it to become hotter. Eventually, the core becomes so compressed and hot that it ignites, and thermonuclear fusion kicks off. At this point, the star stops collecting material from the disc and all the leftover material is free to form planets.



When it comes to the formation of Jupiter, scientists believe it happened in two steps. Initially, tiny chunks of icy rock and dust present in the accretion disc started colliding and forming a planetary embryo. Once this embryo was large enough (about 10 times more massive than Earth), its self-gravity became strong enough to pull in gas and dust directly from the disc During this step, Jupiter gained most of its mass, but it wasn't enough to make it a star. The Sun probably took away most of the mass from the disc leaving almost nothing for Jupiter to become a star.



 



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Why do Venus and Uranus spin backwards?



 



We know that the planets in our solar system orbit the Sun and rotate around their own axis in a counterclockwise (west to east) direction. But while all the planets orbit the Sun in this direction, not all of them rotate the same way around their own axis. Venus and Uranus rotate clockwise (east to west), also called retrograde rotation. During the formation of our solar system these two planets spun the same way as others, but there is no definite answer as to when and why they started spinning backwards. However, there are several theories.



The backward-spinning Venus



There are two main theories that try to explain Venus backward / retrograde rotation. The first theory suggests that at some point in time, post the formation of the solar system, Venus flipped its axis 180 degrees. This means, Venus continues to spin in the same direction as it always has, except it is now upside down. So, when looked at from other planets, Venus looks like it is spinning in the opposite direction.



Scientists believe Venus axis might have flipped due to the Sun's strong gravitational pull on the planet's dense atmosphere, which could have caused strong atmospheric tides. These tides, combined with the friction between Venus' mantle and core might have caused the flip.



The second theory states that Venus might not have flipped at all. Scientists propose that the planet's rotation slowed to a standstill and reversed direction. Scientists suggest this theory taking into account the factors mentioned in the first theory coupled with the tidal effects from other planets. They believe this might have caused Venus to eventually spin in a more stable retrograde state.



The side-spinning Uranus



Uranus, like Venus, rotates in the clockwise direction but its axis is tilted at 97.77 degrees, making the planet appear as though it is spinning sideways and orbiting the Sun like a rolling ball. The most popular theory suggested by scientists for Uranus tilt is the collision of the planet with an Earth size object. A more recent theory suggests that Uranus wasn't hit once by a giant object, but collided multiple times with objects of a smaller size.



A collision-free theory suggests that during the initial days of planetary migration, Uranus had a large Moon whose gravitational pull caused the planet to fall on its side. During the same planetary migration, this moon is believed to have been knocked out of orbit by another planet.



 



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