Space debris represents a serious threat to future satellites. Credit ESA.

A hot topic in space, and an increasingly alarming danger, is the presence of space debris orbiting the Earth: fragments of satellites and spent rocket stages travelling at high velocity, and often in orbits where we want to place operational satellites.

According to the European Space Agency, there are 8,800 tonnes of space debris consisting of over 34,000 pieces that are more than 10cm in size, and 128,000,000 pieces smaller than 10cm in size, in orbit. …


The brilliant 16th century astronomer who built Uraniborg: a renaissance masterpiece and the astronomical wonder of the world

On the 14th Dec 1546 a boy was born who would grow up to be the greatest observer of the skies who had ever lived. His name was Tycho Brahe.

Tycho’s great achievement was to make observations of the stars and planets (including a supernova and several comets) that were so accurate that they ended up overthrowing previous held beliefs:

· that the Earth was the centre of the Universe

· that the planets moved around the Earth in perfect circles, embedded in perfect crystalline spheres

· that there could be no change in the skies beyond the orbit of…


Extraordinary Claims Require Extraordinary Evidence

The planet Venus. Long thought to be Earth’s ‘twin’, its average surface temperature is 460⁰C and surface pressure 90 times Earth’s making it extremely hostile to life. Its atmosphere consists of dense clouds of sulphuric acid which are also very unwelcoming for life; however there are ‘acidophiles’ on Earth that prefer acidic conditions. Credit: Wikimedia Commons

To be fair, the authors of a recent paper announcing the discovery of the gas phosphine in the atmosphere of Venus did not claim to have found life.

But they do point out that phosphine is only produced naturally by living things on Earth (rather than, say, by volcanism) and its value as an indicator of life in the atmospheres of other planets was already recognized.

They tried extremely hard to determine whether phosphine could be produced by non living things in the conditions of Venus’s atmosphere. They couldn’t. …


How Physics Was Introduced Into Astronomy For The First Time

The motion of the ‘star’ Mars according to Ptolemy, from a first edition of Kepler’s Astronomia Nova (1609). Image credit: Bonhams

It may seem amazing to us now, but astronomy and physics were once completely disconnected from each other. Prior to the early 17th century astronomy was considered a branch of mathematics, and physics a branch of philosophy.

It was the ancient philosophers Plato and Aristotle who between them declared that the planets, Sun and moon moved in perfect circles at uniform speed around the stationary Earth. The job of astronomy was then to account for the observed positions of these bodies in terms of uniform circular motions. …


Saturn’s moon Titan has more in common with the Earth than any other known world

Saturn, the jewel of our Solar System. Image credit: NASA/JPL-Caltec/Space Science Institute

The Solar System contains a diverse range of worlds, from the four rocky inner planets to the outer four gas giants which have between them over two hundred known moons. In addition, there are countless millions of other objects including dwarf planets (of which Pluto is one), asteroids and comets. Many of them have been the subject of intense study whether by telescope or visiting spacecraft.

But most of these worlds are very different from the Earth. Mercury and almost all the moons and asteroids have no atmosphere to speak of and most have ancient, geologically inactive surfaces pockmarked with…

Brian Skidmore

Architect for the Lunar Pathfinder mission at SSTL. Masters in Radio Astronomy (Jodrell Bank, UK) and Natural Sciences with Physics and Astronomy (OU, UK).

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