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Covers of How We Came to Know the Cosmos: Space and Time and How We Came to Know the Cosmos: Light and Matter

First published on 5th August 2017. Last updated on 26th October 2017 by Dr Helen Klus

We live in a universe that is both infinite and ever expanding, that contains dimensions we can never see, and places we can never go, even if we travelled forever. There may be millions of other planets in our galaxy that contain life and there may be multitudes upon multitudes of multiverses. This may mean everything that’s physically possible is actually happening somewhere.

Modern science has become so astonishing that many people find it difficult to believe. How We Came to Know the Cosmos addresses this by showing how we came to such bizarre conclusions from first principles. »

Spectroscopy and biosignatures: How we'll find evidence of life on other planets

The spectra of the Sun showing spectral lines.

First published on 22nd April 2017. Last updated on 26th October 2017 by Dr Helen Klus

Scientists have found thousands of planets outside of the Solar System, many of which are thought to be habitable. The next step is to search for signs of life. While this may be possible with current and upcoming telescopes, like the Hubble Space Telescope (HST) and the James Webb Space Telescope (JWST), NASA is currently considering two projects that will be able to directly image Earth-like planets. »

Ancient aliens: Could fast radio bursts be powering extragalactic spaceships?

Image of a solar sail in space.

First published on 11th March 2017. Last updated on 26th October 2017 by Dr Helen Klus

Scientists at Harvard University have recently suggested that intelligent life forms in another galaxy may have used interstellar spacecraft billions of years ago. Their paper, co-authored by Manasvi Lingam and Abraham Loeb and entitled ‘Fast Radio Bursts from Extragalactic Light Sails', has just been published in The Astrophysical Journal. »

Life in crystals: The science of crystal gems

Photograph of a person surrounded by giant crystals.

First published on 26th February 2017. Last updated on 26th October 2017 by Dr Helen Klus

Crystals are objects with atoms that are arranged periodically. This can be seen on a large scale as they form natural cubes, triangles, or more complex symmetrical shapes like snowflakes. Many crystals are minerals. Minerals are naturally occurring solids with a potentially crystalline structure that are not made by life forms. They are made from single elements or molecules that form a repeating pattern. New atoms attach in such a way that the pattern is repeated on every scale, making them natural fractals. »

What are facts?: The difference between scientific hypotheses, theories, and laws

Photograph of the Earth taken from the International Space Station.

First published on 16th February 2017. Last updated on 26th October 2017 by Dr Helen Klus

A scientific law states what happens. This is often a mathematical relationship between two or more things. A theory will never become a law; theories and laws are two separate things. Both have been thoroughly tested, and so both are often referred to as facts. »

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The Star Garden is a science news and science education website run by Dr Helen Klus.

How We Came to Know the Cosmos covers the history of physics focusing on space and time, light and matter, and the mind. It explains the simple discoveries we made in prehistoric times, and how we built on them, little by little, until the conclusions of modern theories seem inevitable. This is shown in a timeline of the universe.

The Star Garden covers the basics for KS3, KS4, and KS5 science revision including SATs, GCSE science, and A-level physics.