From time immemorial, curious humans have questioned our place in the universe. A child asks “why, why, why”, and the parent answers “because, because, because”. In the brutish Old Stone Age, humanity imagined unseen conflicts in the cosmos, foretold in the patterns of the stars. By the New Stone Age, priests in temples skilfully pronounced on omens from capricious gods. The papyrus age had scribes who recorded philosophers’ thoughts on the fabric of the heavens. Then, in the telescope age, craftsmen reflected and refracted the visible and the invisible celestial rays to produce marvellous images of heavenly realms, adding colour to scientific accounts.
Today, in the Information Age, Jillian Scudder has grasped her Twitter handle, opened her Facebook page and spent five years answering questions from thousands of followers of her blog, Astroquizzical . “Why do we only see one side of the Moon?” tops her list of frequently asked questions. Another favourite is: “are all pictures of space false colour, even the NASA ones?” Scudder is an astrophysicist who studies star formation in very distant galaxies but takes time out to passionately engage in outreach, getting into schools and the community as often as she can. This, her first introductory book on astronomy, benefits from that outreach.
The narrative form that Scudder employs is an imaginary cosmic journey that begins on our home planet and takes us in seven steps to the furthest galaxies. This simple format has been tried countless times before by big-name astronomers. What’s different here is an intense level of engagement between writer and reader. Vivid storytelling explains the physics without equations. We are told that gravity rules the universe at all scales. Through a family tree analogy, Scudder traces our cosmic origins. Our parent is Earth, and our grandparent is the Sun. Our solar system formed in an interstellar dust cloud, which in turn condensed within the Milky Way, a member of a cosmic web of galaxies.
Readers have homework to do: there are eight thought experiments, a means of instruction advocated by Albert Einstein, no less. One of them is about a hypothetical interplanetary system for transporting the building blocks of life from elsewhere to Earth. Another reflects Scudder’s take on the weirdness of life. She invites us to sniff at repulsive mats of sulphate-reducing bacteria known as snoticles, hanging from the ceilings of caves. Her aim is to get people to think issues through for themselves, and that works.
The clarity of Scudder’s writing is impressive. Her explanation of false colour images candidly explains that they “are manipulated to reflect the beauty of the image”. That’s because the raw data from a space telescope is a series of digital black and white maps, made at wavelengths to which our eyes are insensitive.
Scudder also challenges the myth that black holes have voracious appetites by pointing out that they are extraordinarily inefficient at swallowing external matter. Mostly the in-falling mass releases vast amounts of energy as it tumbles towards the event horizon, where it is promptly blasted back into space by cosmic jets. Unfortunately, the book demotes dark matter to a four-line footnote, and ignores dark energy. Readers are thus left in the dark on the biggest story in modern cosmology.