![\"Could](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/06\/star-trek-teleportation-b13db08.jpg\")
Credit: CBS Photo Archive \/ Getty Images<\/p>\nI\u2019m convinced that, when I was a physics student, a lecturer quoted: “There\u2019s speculation, then there\u2019s more speculation, then there\u2019s cosmology.”<\/p>\n
But when I recently tried to track down a source for these words of wisdom, three were mentioned: the cosmologist Edward Harrison, the physicist Lev Landau and, rather embarrassingly, me.<\/p>\n
So maybe I made it up. But that doesn\u2019t mean there are no grounds for concern.<\/p>\n
Credit: CBS Photo Archive \/ Getty Images<\/p>\n
Science and the problem with the truth<\/p>\n
Science depends on our ability to test theories. Some mistakenly think it\u2019s about uncovering the truth \u2013 it\u2019s not.<\/p>\n
Science is always provisional, but it attempts to give us the best theory based on current evidence.<\/p>\n
The reason cosmology will always carry a strong aroma of speculation is that experiments are rarely possible.<\/p>\n
Even observational evidence is usually indirect, relying on building assumption on top of assumption, leaving a dangerously crumbly edifice.<\/p>\n
Something that doesn\u2019t help is an attitude brilliantly summed up in a quote that is legitimately attributed to Lev Landau: “Cosmologists are often in error but never in doubt.”<\/p>\n
To take two examples: with limited supporting evidence, the theories behind cosmic inflation and dark energy are regularly presented as fact.<\/p>\n
![\"This](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/06\/2.-Abell-370-dragon-arc.jpg\")
This image of Abell 370, a galaxy cluster 4 billion lightyears away, shows several arcs of light, including the ‘Dragon Arc’ (lower left of centre). These arcs are caused by gravitational lensing, when light from distant galaxies is warped by the cluster’s gravity. Credit: NASA, ESA\/Hubble, HST Frontier Fields
\nWhy space science is so difficult<\/p>\n
Astronomers do amazing jobs providing data to feed into these theories, but they face many challenges.<\/p>\n
They are scanning vast distances, looking back billions of years, dealing with all manner of obstacles that get in the way of certainty.<\/p>\n
The Biblical wording, “For now we see through a glass, darkly,” could describe the challenges faced by astronomers.<\/p>\n
Take the measurement of interstellar and intergalactic distances<\/a>, without which we couldn\u2019t detect the accelerating expansion of the Universe<\/a>.<\/p>\n Clearly, no one has been out there with a tape measure. Once an astronomical body is far enough away for the optical mechanism of parallax to fail, we become dependent on ‘standard candles’.<\/p>\n If we know how bright specific types of star and supernovae<\/a> really are, we can use apparent brightness to establish their distance.<\/p>\n But there are plenty of assumptions in play, some of which are beginning to look doubtful.<\/p>\n Things get even murkier with \u2018inflation\u2019. This was a patch to fix a problem in Big Bang theory.<\/p>\n Fred Hoyle, a member of the group behind the early alternative, steady state theory<\/a>, was always furious that the Big Bang was repeatedly patched up, but steady state was dismissed as soon as contradictory evidence emerged.<\/p>\n![\"Illustration](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/06\/1782554178_72_big-bang.jpg\")
Illustration depicting the Big Bang. Credit: Marck Garlick \/ Science Photo Library \/ Getty Images
\nThe heart of the Big Bang<\/p>\n