“The question of communication, trust, and accountability of science is now front and center in the scientific community,” Kennel said. While Climategate was not the reason the SSB decided to hold this workshop, he noted that it was happening while the workshop was planned.

ROGER-MAURICE BONNET

Bonnet provided a broad overview of the five “Grand Questions”—what has been learned in the past 50 years of space science research and today’s understanding of what research is needed to continue finding answers to them. Fifty years ago, he said, scientists were interested in discovery, not grand questions. They did not care what they would discover because they knew they would discover something. Discovery was the message they wanted to convey.

After 50 years and the use of space-based and ground-based telescopes, astronomy, which in the beginning was a science of the visible, is “more and more a science of the dark.” The power of telescopes has increased this “zone of uncertainty, darkness” where models are used to understand what you do not see. Spacecraft opened a new era in the darkness because we can look at the entire spectrum. We look “at all the lights emitted by the universe. We have observed the whole electromagnetic spectrum for understanding fundamental physical processes, we have discovered new objects, [and] we have discovered gamma rays, x-rays, and black holes … astronomy became something new.”

Interplanetary spacecraft allow us to look at the universe outside of Earth’s influence and outside of the plane of the ecliptic in which all the planets orbit the Sun. For 18 years, for example, we have observed the Sun and the heliosphere from above.

We have discovered “flabbergasting objects” like Io, a moon of Jupiter with active volcanoes, and the icy surface of Europa, which may have an ocean beneath it. We have made “fantastic progress in understanding the universe,” he said.

We have also landed on the surface of the Moon, Mars, Venus, and Titan. We have imaged a comet’s nucleus and will land on one of them in 2014. We have explored the heliosphere and are now moving into the interstellar medium with the Voyager spacecraft.

But for all of these discoveries, Bonnet commented, the space science community has netted only two Nobel Prizes: Riccardo Giacconi in 2002 for the first detection of an x-ray source in the universe, and John Mather and George Smoot in 2008 for measurements of the cosmic background.

He then provided an assessment of the current status of answering the five Grand Questions identified by the workshop organizing committee.

Understanding the Universe: How Did It Begin and How Is It Evolving?

Calling the universe a “strange machine” and comparing its shape with a trumpet or a “cosmic vuvezela”—a reference to the noisy trumpet popular with soccer fans in South Africa—Bonnet explained that, according to modern day cosmology, the universe began with a Big Bang, expanded, and then decelerated and reaccelerated. Several space missions have observed this, he said, including the Cosmic Background Explorer, the Wilkinson Microwave Anisotropy Probe, the Planck observatory, and the Hubble Space Telescope.

These spacecraft and ground-based instruments have showed, however, that what we see (i.e., visible matter) is only a small part of the universe—5 percent. Dark matter is 25 percent, and dark energy is 70 percent. What are these things? That is what astronomers are trying to answer. We know there is dark matter, although it is difficult to detect because it interacts with nothing. It can be detected by observing the deformation of distant galaxies when they pass through dark matter and their shape is modified. The “mystery” of dark matter will probably be resolved both through astronomy and particle physics using accelerators like CERN (European Organization for Nuclear Research).



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement