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View from a Scope | October 20, 2017

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Questions & Answers

Astronaut (1)

Could an Astronaut be rescued if he/she became untethered on a space walk?

NASA has developed a sort of jetpack called SAFER (Simplified Aid For EVA Rescue) which fires compressed nitrogen from 24 thrusters to steer the astronaut back to safety if they become detached.

Theoretically, astronauts could also vent some gas from their suits or even throw a tool in the opposite direction to push themselves forward.

But the problem is unless the thrust is exactly in line with the astronauts centre of mass, they will start spinning uncontrollably and very quickly become disorientated.

SAFER automatically detects rotation and uses its jet to keep the astronaut orientated the same way.

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Earth (3)

Why does the Moon affect Earth’s tides more than the Sun?

The tides are a result of the difference between the forces of gravity on opposite sides of the Earth. Because the Earths diameter is such a small fraction of the Sun-Earth distance, the gravitational pull only changes by 0.017% across the Earth. But for the moon that difference is 6.8%, 400 times greater. If you factor in the overall stronger pull from the Sun this means that the Sun’s tidal effect is only 44% that of the Moon.

Where did Earth’s water come from?

There is approximately 1,450 million billion tonnes of water in the worlds oceans. There are two main theroes about where it all came from.

1. On early Earth, hydrogen and oxygen molecules combined and emerged as steam from volcanic eruptions.

2. Ready made water molecules arrived from Earth from comets which would have being bombarding the early Earth.

What is the largest Volcano in the Solar System?

Until recently the largest volcano in the solar system was thought to be Olympus Mons on Mars. However, recent research has revealed that the Tamu Massif, a submerged shield volcano 1,600km east of Japan is actually larger.

The Tamu Massif, which erupted between 130 and 145 million years ago, is about 640km wide and covers and area of about 190,000 square kilometres.

In comparison, Olympus Mons  is only 595km across, although it is thought to be 25% more massive overall.

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Moon (1)

Why Doesn’t the Moon have an atmosphere?

The moon has an atmosphere, it is just very very thin. the amount of atmosphere a planet or moon has depends on its gravity. Because the moon has a gravity 1/6th of Earths, it is unable to hold onto the atoms and molecules that would make up its atmosphere.

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Solar System (1)

What is the largest Volcano in the Solar System?

Until recently the largest volcano in the solar system was thought to be Olympus Mons on Mars. However, recent research has revealed that the Tamu Massif, a submerged shield volcano 1,600km east of Japan is actually larger.

The Tamu Massif, which erupted between 130 and 145 million years ago, is about 640km wide and covers and area of about 190,000 square kilometres.

In comparison, Olympus Mons  is only 595km across, although it is thought to be 25% more massive overall.

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Space (5)

Why is there no oxygen in space?

There is oxygen in space, although the density of it is about 100-billion-trillioniths of the density in the Earths atmosphere. Oxygen is actually the third most common element in the universe

Which came first – Time or Space?

According to Albert Einstein, space and time are different aspects of the same entity now called “spacetime”. It therefore seems plausible that they came into existence simultaneously. That said recent research combing Einstein’s work with quantum theory has led some theorists to conclude that space may actually give rise to a phenomenon we experience as time.

When will the Milky Way and Andromeda collide?

It has being known for decades that our nearest galactic neighbor the Andromeda galaxy has been heading towards us at a rate of 120km/s. It was only recently that astronomers were sure whether or not Andromeda would score a direct hit.

While its is relatively easy to measure the approach speed it is far more difficult to measure its exact direction of motion. But a few months ago astronomers using the Hubble telescope finally pinned down its trajectory.

The Andromeda Galaxy is going to score a direct hit with the Milky Way in about 4 billion years time.

 

Could an Astronaut be rescued if he/she became untethered on a space walk?

NASA has developed a sort of jetpack called SAFER (Simplified Aid For EVA Rescue) which fires compressed nitrogen from 24 thrusters to steer the astronaut back to safety if they become detached.

Theoretically, astronauts could also vent some gas from their suits or even throw a tool in the opposite direction to push themselves forward.

But the problem is unless the thrust is exactly in line with the astronauts centre of mass, they will start spinning uncontrollably and very quickly become disorientated.

SAFER automatically detects rotation and uses its jet to keep the astronaut orientated the same way.

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Stars (2)

What is the fastest-spinning star ever found?

A Hot blue star 25 times the mass of the sun, is the fastest-spinning star known. It is called VFTS 102 and it resides within the Tarantula Nebula. At its surface the star rotates at about 600km/s (more than 1 million mph). Although VFTS 102 is the fastest rotating ‘normal’ star, pulsars actually spin more quickly. Pulsars are the collapsed cores of stars that have gone supernova. The fastest spinning pulsar discovered is Ter5ad. It rotates 716 times a second, which means the rotation speed at its equator is about 158 million mph or about 24 per cent the speed of light.

Do Stars spin on their axis like planets?

Stellar rotation is usually the result of the rotation in the gas cloud that condensed to form the star. However unlike planets stars are not solid bodies so their rotation is not always simple.

Firstly stars like many planets suffer from equatorial bulges. The faster the rotation, the more pronounced the bulge. Many stars also show differential rotation where the rotation at the equator is faster than the rotation at the poles.

Pulsars which are magnetized remains of exploded stars, rotate very quickly. Around 716 times every second!

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Sun (2)

How do we know how hot the Sun is?

The sun is around 5,500 degress celsius. the most accurate method to measure the temperature relies on the fact that elements in the solar atmosphere absorb radiation, which wavelengths are absorbed and by how much also depends on the temperature

How many planets will be engulfed when the Sun dies?

In 5 billion years, the sun will expand to become a ‘red giant’. It will engulf the planets Mercury and Venus, but the Earths fate is less clear. As the Sun swells up to 250 times its present size, it will lose more than a third of its mass to the strong stellar winds. This will cause the planets orbits to widen significantly so the Earth may just escape the out-rushing Sun. However at this point our planet will have been long dead, 3 billion years from now the Suns energy output will evaporate the oceans.

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