Big questions, big projects
Tackling the biggest open questions in science increasingly demands financial and human resources on an international scale. ‘Big science’ projects typically take decades to plan and build, and further decades to operate. As well as shedding light on the smallest constituents of matter and the earliest moments of time, big science aims to address our growing energy demands.
A new kind of science has emerged over recent decades. Previously, researchers could satisfy their curiosities with laboratory equipment; however, tackling the most fundamental questions about the Universe far exceeds the capabilities of research groups, institutes and even nations. It can take decades to develop, construct and operate such experiments.
Three projects spanning the physical sciences illustrate the enormous feats and challenges of twenty-first century ‘big science’, ranging from esoteric quests for the fundamental constituents of matter to technology that will recreate the nuclear powerhouses of stars to meet increasing energy demands.
THE HIGH-ENERGY FRONTIER
In September 2008, physicists began to operate the largest scientific instrument ever built: the Large Hadron Collider (LHC)1 at the European Organization for Nuclear Research (CERN). This 27-km-circumference ring, lying approximately 100 metres (m) beneath the surface on either side of the Swiss–French border, took 15 years to build, cost more than €3 billion, and will spend the next 15 years accelerating protons and atomic nuclei to almost the speed of light before smashing them together 40 million times per second. Surpassing the energy and collision rate of previous particle colliders by up to two orders of magnitude, the LHC will replicate the enormous energy densities that were present just
Testament to the huge engineering challenges posed by such a project, which relies on maintaining thousands of high-powered superconducting magnets at –271 °C, the LHC suffered a major electrical fault just days after it was switched on. In late 2009, however, the collider delivered its first tentative data to the four giant detectors sited around the ring where the particles collide, opening a new era in particle physics.
The largest of these detectors — the Toroidal LHC Apparatus (ATLAS)2,3, which weighs 7,000 tonnes, and is 45 m in length and 25 m in diameter — was designed, built and operated by an international collaboration of 2,800 scientists from more than 160 institutions in 36 nations. It consists of several layers of highly sensitive particle detectors and huge superconducting magnetic coils, which allow it to measure precisely the paths and energies of particles emerging from the interaction region (pictured above). Over the next two decades, the ATLAS collaboration will search for new fundamental particles that explain the origin of mass or account for the ‘dark matter’ that makes up most of the mass in the Universe, possibly opening doors to new dimensions of space–time.
The Hubble Space Telescope (HST) has returned iconic images of the Universe for 20 years, including photographs of galaxies further than 12 billion light years away, and its data underpin more than 8,500 scientific papers. However, a new optical telescope can surpass the HST’s image resolution by a factor of 10. The Large Binocular Telescope, located high up in Arizona’s Pinaleno Mountains, is the result of a consortium between institutes in the United States, Italy and Germany4. It boasts the two largest telescope mirrors in the world, each measuring 8.4 m across, which combine light coherently to produce an image with sharpness equivalent to a single 22.8-m-diameter mirror (pictured above right). This unrivalled high-resolution imaging will allow the LBT to search for extrasolar planets that are young counterparts of the Earth, address how super-massive black holes at the centres of galaxies form, study early epochs in the expansion of the Universe, and shed light on stellar and planetary formation.
The technical challenges are enormous: a 650-tonne structure holds two 55-m2 pieces of glass in shape, with a precision better than a micrometer, within a 13-story-high rotating steel building at an altitude of 3,200 m. The LBT relies on an adaptive optics system that adjusts the shape of its mirrors up to 1,000 times per second to counteract the blurring effects of the Earth’s atmosphere and thereby avoids the need to launch a telescope into space, which would be even more complex and costly.
The US$100 million LBT saw ‘first light’ in 2005, and became the world’s largest functional light-gathering machine in 2007 (ref. 5). By 2012, it is scheduled to operate in full function, to give us pictures of the cosmos with unprecedented clarity.
HARNESSING STAR FUEL
Big science is not solely focused on fundamental knowledge. At the Cadarache research centre for nuclear energy in France, construction of a €15 billion experiment called ITER (formerly International Thermonuclear Experimental Reactor), which should demonstrate the feasibility of generating electricity via nuclear fusion6-8.
For half a century, researchers have tried to recreate on Earth the practically limitless energy source that powers the stars: a process whereby light nuclei (isotopes of hydrogen) fuse into heavier ones and release large quantities of energy. Whereas a typical coal-fired power station consumes 3 million tonnes of fuel per year and emits almost four times as much carbon dioxide, a commercial fusion power station could produce the same electrical output using just 100 kg of deuterium and a few tonnes of lithium without releasing any greenhouse gases.
ITER, which is jointly conducted by Europe, China, Japan, Korea, India, Russia and the United States, will allow researchers to study high-temperature plasma physics under genuine reactor conditions. The 20,000-tonne device will use superconducting magnets to confine 600 m3 of plasma at approximately 100 million °C inside a doughnut-shaped vessel called a tokamak. This technology presents serious engineering challenges. Conceived in 1985, ITER will operate for at least 15–20 years from 2026 and should pave the way for a demonstration fusion power plant.
THE FUTURE IS BIG
Unravelling the mysteries of the Universe and addressing imminent problems facing humanity increasingly requires large-scale projects that can be accomplished only by international collaborations. All three projects described here require sustained human, financial and technological resources for at least 20 years, as well as considerable diplomacy: it took several years to settle upon a site for ITER, for example. In return, such projects provide unsurpassed prospects for high-tech developments and scientific results that will occupy generations of world-leading researchers.
The Max Planck Institute of Physics has developed and constructed essential parts of the ATLAS detector (Aad, G. et al. J. Instrum. 3, S08003, 2008). The Max Planck Institute for Astronomy designed the near-infrared beam combiner for the Large Binocular Telescope (Rix, H.-W. and Herbst, T.M. unpublished observations). The Max Planck Institute for Plasma Physics devised a mode of plasma operation for potential use by the International Thermonuclear Experimental Reactor (Gruber, O. et al. Plasma Phys. Control. Fusion 47, B135, 2005).