These are some of my cosmology posts
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The Shortest Day
Updated and revised 11 December 2025 As I write this post, it’s completely dark outside and it’s only 5 o’clock in the afternoon. Today is 4 December, and most people I come across think that it will continue to get dark earlier and earlier in the afternoons until 21 December, the shortest day of the year…
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The Universe’s History: From Big Bang to Today
Updated 20 November 2025 his post covers a brief history of the Universe from the Big Bang until the the present day. This, as I am sure you’ll agree, is a pretty big topic so I’ll only give a outline of some of the key events and when we believed they happened. This post is…
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Philae has landed
Like millions over people I was cheered to see that the probe Philae landed successfully on the 67P/Churyumov-Gerasimenko comet after a 6.4 billion km ten year journey. In a mission this complex there will inevitably be a few hiccups and the biggest one so far has been that the probe has been unable to secure itself to…
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Stardust
Last week I was on holiday in London. While I was there, I spent an afternoon at the Royal Greenwich Observatory, which is set on top of a hill in East London. It was commissioned in 1675, making it one of the oldest astronomical observatories in the world. Sadly, it can no longer function as…
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Space the Final Frontier- but where does it begin?
On 24 October 2014 a senior Google vice president 57 year old Alan Eustace (shown below) broke the world altitude record by jumping from a balloon from an altitude of 135,890 feet (41.4 km). When he was interviewed, after he had safely landed, he said: “..It was beautiful. You could see the darkness of space… “ This made me…
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Virgin Galactic: what next ?
Like many people, I was was saddened to hear about the crash of Virgin Galactic’s Space Ship Two on a test flight yesterday, which resulted in the death of one of the pilots and the serious injury of the other. It is far too soon to say what caused the crash. That will have to wait…
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The Universe Past, Present and Future.
The Universe is all existing matter and space, including all stars, planets, galaxies and the space between them. This post, which is the first in a series about cosmology discusses the origins of the Universe and its ultimate future. (All my posts on this topic can be found at https://explainingscience.org/tag/cosmology/) How large is the Universe ?…
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Artefacts From Earth
This is the final post in a series about human efforts to contact extraterrestrials. Today I want to discuss the objects which have already been sent out into interstellar space in the hope that at some point in the distant future an alien civilisation will retrieve and decipher them. The Pioneer Plaque On 3 March 1972 Pioneer…
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This is Earth Calling
Sending Messages to be picked up by alien civilisations is called METI (Messaging to Extraterrestial Intelligence) and is an activity which has taken place with increasing frequency over the past few decades. Advocates of METI argue that in addition to searching for extraterrestrial signals we can increase our chances of making contact with aliens by sending messages to stars which…
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SETI
As I discussed in my last post, the search for signs of extraterrestrial life has caught the interest of many people for a very long time, and the specific search for signals from other life forms has been a particular source of fascination over the last 50 years. In the 1997 movie Contact Jodie Foster’s…
Explaining Science 