A star with a mass of less than 1.5 solar masses (the mass of the Sun) forms a white dwarf at the end of its lifetime, owing to its gravity being too weak to collapse it further. If the mass of a star is greater than five solar masses, the forces will be so intense that the star collapses past the point of a neutron star and becomes a black hole. However, between these two extremes a neutron star will form as the result of a supernova, although only approximately one in a thousand stars will become one.

As a star runs out of fuel it will eventually collapse in upon itself. In the formation of a neutron star, the protons and electrons within every atom are forced together, forming neutrons. Material that is falling to the centre of the star is then crushed by the intense gravitational forces in the star and forms this same neutron material. Like the Earth, magnetic fields surround neutron stars and are tipped at the axis of rotation, namely the north and south poles. However, the magnetic field of a neutron star is more than a trillion times stronger than that of Earth’s.

The gravitational forces in a neutron star are also incredibly strong. The matter is so densely packed together into a radius of 20 kilometres (12 miles) that one teaspoon of mass would weigh up to a billion tons, about the same as Mount Everest. They also spin up to 600 times per second, gradually slowing down as they age.

Oddly enough, as a neutron star becomes heavier it also becomes smaller. This is because a greater mass means a greater force of gravitational attraction, and therefore the neutrons are squeezed more densely together. In fact, if you were able to drop an object from a height of one metre on the surface of a neutron star, it would hit the ground at about 2,000 kilometres (1,200 miles) per second.

Space

Peer inside a neutron star

We take a look into the heart of one of the most massive objects in the universe.
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Unlike rocky planets such as Earth, the sun does not have a definitive outer boundary. However, the different layers beneath the Sun’s surface are defined by their temperatures and density. Although the core is on average the hottest part of the Sun, the complex relationship between rising heated gases and falling cooled gases create temperature fluctuations within the layers of the Sun itself.

(Image courtesy of NASA)
Space

What is the Sun made of?

We take a look inside the heart and soul of our Solar System.
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To date there have been 42 missions to Mars, with exactly half of them complete failures. Other than the Earth it is the most studied planet in the solar system, and for centuries it has been at the heart of wild speculation and groundbreaking scientific discoveries. Observations of Mars have not only revealed otherwise unknown secrets but also posed new and exciting questions, and it is for these reasons that it has become the most intriguing planetary body of our time. Take a look at the map above to see key geological points of interest as well as the landing and crash sites for several spacecraft.

This image of the surface of Mars was created by reconstructing data from NASA’s Mars Global Surveyor, the Mars Orbiter Laser Altimeter and observations by NASA’s Viking spacecraft.
Space

The surface of Mars

Take a virtual stroll around the Red Planet.
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Rockets like Saturn V, the one used to launch NASA’s Apollo and Skylab programs, are multi-stage liquid-fuelled boosters. The Saturn V is considered to be the biggest, most powerful and most successful rocket ever built.

The Saturn V was 110.6m tall, 10.1m in diameter and had a payload of 119,000kgs to low-Earth orbit.

There were three stages, followed by an instrument unit and the payload (spacecraft). The total mission time for this rocket was about 20 mins. The centre engine was ignited first, then engines on either side ignited. The first stage lifted the rocket to about 70m and burned for 2.5 mins.

When sensors in the tanks sensed that the propellant was low, motors detached the first stage. The second stage continued the trajectory to 176km and burned for six mins. About halfway through this stage’s ignition, the instrument unit took control of calculating the trajectory.

Second stage complete, solid-fuel rockets fired it away from the third stage. The third stage burned for 2.5 mins and stayed attached to the spacecraft while it orbited the Earth, at an altitude of 191.2km.

It continued to thrust and vent hydrogen before ramping up and burning for six more minutes, so the spacecraft could reach a high enough velocity to escape Earth’s gravity.
Space

See inside the Saturn V rocket

This illustrated cutaway of the Saturn V shows the 110m high rocket and its 3 stages in amazing detail with full notes
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