The universe 380,000 years after the Big Bang, 3D printed. © Elsa Ferreira
Astrophysicist David Clements, assisted by a group of students from Imperial College London, has converted the mapping of “the oldest light in the universe” into a 3D printer file. Makery met the man.
London, from our correspondent
In astrophysics, it’s called cosmic microwave background (CMB)—an electromagnetic radiation that can map the universe (which is currently about 13.5 billion years old), whereas it only came about some 380,000 years after the Big Bang.
“When the Big Bang happened, the universe was hot and relatively dense. It was full of plasma. Protons and electrons [which combine to form atoms] were all separate because it was so hot, like a flame,” begins David Clements, astrophysicist specialized in the observation of stars and galaxies hidden by interstellar dust present in the universe, or whose light has been modified by this dust.
“The plasma is opaque,” the researcher continues. “Photons [the particles associated with electromagnetic waves] can’t pass through it. But as the universe expands, it cools, until you reach a point around 380,000 years after the Big Bang, when the electrons and protons can combine for the first time.” And when photons can finally travel through without bouncing off matter. “That’s the moment where the universe became transparent,” he concludes. It’s also the oldest light in the universe, the first to reach observation satellites.
Why is this important? Because the CMB is “the best view of the place we come from”, the researcher replies. “The denser and warmer parts have been gravitationally attracting material to them and gravitationally collapsing themselves. This forms the larger-scale structure, all the galaxy structures, the stars, planets, us… everything that we see today.”
Distorsion, or when Africa appears smaller than it actually is
To capture this moment, this baby universe born 380,000 after the Big Bang, astrophysicists have access to wonderful maps based on data captured by their satellites, in particular Planck, a space observatory developed by the European Space Agency (ESA), with the participation of NASA, in charge of detailing the variations in CMB temperatures and researching the origin of the universe.
But these ultra detailed plans are sometimes difficult to explore. At fault, among other things, is the distorsion created from passing from a (3D) globe to a flat (2D) representation. This change in format “always produces distortion”, the researcher regrets. “On a map of the world, Greenland looks enormous and Africa doesn’t look as big as it really is. Actually, you can take all the other continents and fit them inside Africa and still have room to spare. On a map, it doesn’t look like that.”
Astrophysicists observe maps “scientifically and quantitatively” and use raw data in their calculations. “If you are just using your eyes to visualize the CMB with one of these flat maps, the distortion can be misleading,” says Clements. Whereas with 3D cosmic sculpture, you can simply touch the sphere to feel the usual characteristics.
The 3D printer file developed by the professor and his team is also meant for visually impaired and blind people. “Astrophysics is such a visual field, we get really great pictures, but they don’t reach people who can’t see,” the researcher regrets, who says he has started talking to a PhD student at the University of Sussex who is preparing a thesis on alternative ways of representing astronomy data so that visually impaired people can experience it too.
Image shared by ESA with its 226,000 Instagram followers:
Une photo publiée par ESA (@europeanspaceagency) le
With its palpable relief, 3D cosmic sculpture is a good start, even if the representation differs from the satellite’s raw data—the team had to magnify the bumps and cavities representing the infinite variations in temperature (a scaled model would have been smoother than a billiard ball!), while attenuating the details, in order to make the file lighter and delete what the printer cannot print.
The “famous cold spot” of the universe
“Other than that, it’s all real,” Clements smiles. He emphasizes the fact that we can now identify well-known places in the universe, for example, the “famous cold spot”, where it is particularly cold. This anomaly is probably due to “a very large void in the distribution of the galaxy”, the researcher offers, or, according to other theories, the proof of the presence of a parallel universe… On the cosmic sculpture, this unusually cold temperature is represented by a hole and colored in blue (for the color version).
So far, the technique has been successful. Clements is accompanying another group of students in making a 3D model of the Earth. The data has also been used in virtual reality, in an exhibition at the Royal Society in London in October. “It was pretty funny,” Clements recalls. “You could pretend that you were the Planck satellite. If you walked on the side, you could walk right out of the universe.”
The researcher has made all his research and 3D plans accessible through a Creative Commons licence, which he insists is common among astrophysicists. “Astrophysics as a field has much more open data than any other fields, partly because there is very little you can make money off of, and partly because they use expensive taxpayer-funded equipment, so it’s only fair that anybody can have a look at the data.” Now it’s your turn!
Download the plans in STL format (monochrome) and VRML (color).