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20.Telescope (a little bit of history)

  In 1608 Hans Lippershey, an eyeglass maker, submitted the first patent of telescope. But who made the first telescope, it is not clear. Later on, Galileo improved the design and started applying in Astronomy. This telescope had convex objective lens and concave eyepiece lens. In 1611 Kepler developed the design using convex lens in both objective and eyepiece and this design was more useful than the previous one developed by Galileo. Diagram of Galilean and Keplerian Telescope In 1655 Huygen was making powerful and enhanced Keplarian telescopes using compound eyepiece but those telescopes were proved inaccurate. In 1688 Isaac Newton built the first reflector telescope which consisted of a tiny flat diagonal mirror to reflect the incoming light on an eyepiece. Using achromatic lens, in 1733, Chester Moore Hall built a telescope. First Reflector Telescope built by Newton Diagram of Achromatic Lens When light of white color passes through a medium it splits into several colors. For exam
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Madness of Magnetar

Magnetar

 What's a Magnetar:

A magnetar is a type of neutron star believed to have an extremely powerful magnetic field (approximately 109 to 1011 tesla). The magnetic field decay powers the emission of high-energy electromagnetic radiation, particularly X-rays and gamma rays. Like other neutron stars, magnetars are around 20 kilometres in diameter and have a mass 1.5 to 2 times that of the sun. The density of the interior of a magnetar is such that a tablespoon of its substance would have a mass of over 100 million tons.

Magnetars are differentiated from other neutron stars because of having even stronger magnetic field and rotating comparatively more quickly.

Some properties:

The active life of a magnetar is short. Their strog magnetic field decay after about 10,000 years. After which activity and strong X-ray emission ceases. One estimation puts the number of inactive magnetars in the Milky Way at 30 million or more.

At a distance of halfway from Earth to Moon, a magnetar could erase all the information from the magnetic strips of all credit cards on Earth. The magnetic field of a magnetar would be more lethal at a distance of 1000 kilometres. Due to the strong magnetic field distorting the electron clouds of the subject’s constituent atoms, making the chemistry of life impossible. Magnetars are the most powerful magnetic objects detected throughout the universe.


A real Magnetar

How a Neutron Star becomes a Magnetar?

When in a supernova a star collapses and turns into a neutron star, its magnetic field increases tremendously in strength. Having a linear dimension increases the magnetic field fourfold. It is calculated that when the spin, temperature and magnetic field of a newly formed neutron star falls into the right ranges, a dynamo mechanism could act, converting heat and rotational energy into magnetic energy which increases the magnetic field from 108 teslas (this amount is already enormous) to more than 1011 teslas. The result is a magnetar. It is estimated that about one in ten supernova explosions results in a megnetar rather than a more standard neutron star.

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