The Sky at Night TV show, past, present and future
Inside the Sky at Night
In the June episode of The Sky at Night, Astronomer Royal Martin Rees takes a look back over the last 50 years of astronomical innovations and progress.
As every reader of BBC Sky at Night Magazine knows, astronomy is on a roll – and has been for the last 50 years. Increasingly powerful observational techniques, in space and on the ground, have revealed a succession of surprises. As someone old (and lucky) enough to have had a ringside seat over this whole time-span, I’ve been glad to contribute some thoughts to the June episode of The Sky at Night, which will dig into its archives to find footage of some of the astronomers and instruments who spearheaded a number of these key discoveries.
In 1964 the discovery of cosmic background radiation – the afterglow of creation – settled the debate between the ‘steady state theory’ and the ‘Big Bang’ explanations of how our Universe came into being. We can now speak with confidence about what our cosmos was like right back to just a nanosecond after the ‘beginning,’ and speculate back even further. Einstein’s theory of gravity – general relativity – dates back to 1915, but had a resurgence in the 1960s, stimulated by advances in cosmology. Perhaps even more importantly, though, was the discovery of phenomena – such as pulsars and binary stellar-mass black holes – for which Einstein’s theory was not just a tiny correction to Newton, but crucial to understanding them.
A whole raft of observations accumulated during the 1970s, which indicated galaxies weren’t mainly made of gas and stars but contained a third key ingredient: dark matter, that contributed five times more gravitating material than ordinary atoms.
Because we can’t do actual experiments on stars and galaxies, astrophysics has been hugely boosted by the advent of powerful computers. We can now build virtual worlds, and see what happens when galaxies form or stars collide.
Astronomers everywhere
Astronomers have also become a global community and European collaboration has become especially strong in recent decades. ESA has launched missions – Gaia and Planck, for instance – with strong UK participation. Moreover, optical astronomy in the UK was boosted by the decision to join ESO and gain access to facilities like the VLT – by most criteria the world’s number-one optical telescope.
It has, more generally, been gratifying to see the expansion of the UK’s astronomy and space community, as an increasing number of universities have turned their physics departments into ‘physics and astronomy’. And the widening of interest in astronomy has been stimulated by the greater capabilities of amateur-scale telescopes, and by internet-based citizen science projects such as Zooniverse.
The pace of discovery certainly isn’t slackening. Two very different research fields are surging forward fast. One is gravitational waves. LIGO and VIRGO have detected the ripples in space from colliding black holes and neutron stars a billion lightyears away – atechnical challenge equivalent to measuring a change at the distance of Alpha Centauri by the thickness of a hair. The other is exoplanets: the realisation that most stars are orbited by retinues of planets. Millions are ‘habitable’ – perhaps we’ll learn in the next 50 years whether they’re actually inhabited.
Be that as it may, when the history of science in the last 50 years is written, astronomy and space exploration will surely provide many of the most exciting chapters. Many issues that perplexed astronomers in the 1960s have now been settled; and we’re now tackling questions that couldn’t even have been posed back then. So the coming decades promise to be as exciting as the last few have been. But progress will, as in the past, be owed primarily to better technology, not to armchair theorists like me.
Martin Rees is the Astronomer Royal and served as President of the Royal Society from 2005 – 2010
Looking back: The Sky at Night
10 July 1974
On the 10 July 1974 episode of The Sky at Night, Patrick Moore took an image of the red supergiant star Antares. Also known as Alpha Scorpii, Antares is the brightest star in the constellation of Scorpius and is often referred to as The Heart of the Scorpion.
In the northern hemisphere, it is visible as a sparkling red gem in the summer evening sky alongside its much dimmer companion, Antares B. While Antares has a visual magnitude which varies between mag. +0.6 and +1.6, Antares B is a mere +5.5, meaning it is just visible to the naked eye, but its light is swamped by the nearby supergiant.
The star’s red colour is due to the fact it is in the latter stages of its life span, and has begun to run out of hydrogen fuel in its core. This creates a chain reaction that results in it expanding out many times its original size – its radius is over three times the distance between the Earth and the Sun. This expansion has caused the outer layers to cool to around 3,500ºC, about 2,000ºC cooler than the Sun, meaning it appears red in colour, and radiates heavily in the infrared.
As the star progresses into the final stages of its life, it will one day become a supernova. Exactly when this will happen is uncertain, but it will be within the next 10,000 years – relatively soon in astronomical terms.
The Sky at Day
We all know what it’s like to plan a night of stargazing, only to find it’s forecast to be cloudy…again. So this month the team explore what you can see in the sky during the day. From the Parker Solar Probe to solar observing, Chris and Maggie take a look at what our Sun has to offer, while Pete Lawrence reveals other kinds of celestial phenomena before sunset.
BBC Four, 11 July, 10pm (first repeat BBC Four, 14 July, time TBC)
Check www.bbc.co.uk/skyatnight for more up-to-date information
