sci18002 — Announcement

James Webb: It’s worth the wait!

12 July 2018

As you are undoubtedly aware, NASA has recently announced, that the launch of the NASA/ESA/CSA James Webb Space Telescope has been delayed until 30 March 2021. Admittedly, one’s first, emotional, reaction is a sense of frustration, in particular for those scientists who prepared their applications for observing time with James Webb months ago. After all, we are all eager to exploit this fantastic, transformational telescope, and we would like to have it in operation as soon as possible. As scientists, however, we must be rational and overcome our emotions. Those of us who are old enough to have participated, with enthusiasm but also with anguish, in the incredibly successful and eventful life of Hubble are fully aware of how critical each detail, however small, can be for a telescope in orbit. During its 28 years (and counting) of operation Hubble has overcome several dreadful, potentially mission-ending problems; and yet, every time, like a phoenix, it has risen from these problems, sharper and more efficient than ever. Hubble, however, had the advantage of being refurbishable; James Webb does not. This is why James Webb must be perfect at launch, with no single detail or element left unchecked. And this is why we should appreciate and support NASA’s decision to postpone the launch until everything is vetted and confirmed.

James Webb will revolutionise fundamental astrophysics. It will have more than six times the light collecting power of Hubble. Its versatility will allow it to exploit emergent new scientific areas, whether in cosmology, stellar, exoplanet or solar system research. The synergy between James Webb, ALMA and 30-metre-class ground-based telescopes will allow us for the first time ever to witness directly the formation of stars and planets at the present time and at the dawn of the Universe.

James Webb will provide breakthrough observations of the first stages of galaxy formation. A single imaging deep field on James Webb will likely detect several tens of galaxies at redshift larger than 10, when the Universe was less than 500 million years old. James Webb also has the potential to reach redshifts of about 20, pushing back beyond a time only 200 million years after the Big Bang.

James Webb will provide crucial insights into the complex processes of star and planet formation. Coronagraphic imaging of individual protostars at mid-infrared wavelengths will reach contrast ratios from 10–5 to 10–8 at separations from one to about four arcseconds. As a result, James Webb will resolve detailed structures in protoplanetary disks, and obtain spectra of Jupiter-mass gas giants around young stars within about 100 pc of the Sun. James Webb will be a unique asset for characterising the atmospheric properties of transiting planets, with the prospect of probing the atmospheres of Earth-like planets.

Space-based astronomy in general is also a key player in bringing science to the public. Hubble, Chandra, XMM-Newton, Spitzer, Herschel, Planck, Cassini, Rosetta and the others have transformed the way we view the Universe, and brought images of complex astrophysical phenomena into our daily lives. Like those observatories, James Webb will not only inspire a new generation of students and scientists, but astound and excite the public at large. It will be worth the long wait.



Monica Tosi
INAF, Osservatorio Astronomico di Bologna

About the Announcement



The James Webb Space Telescope
The James Webb Space Telescope

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