In order to observe the Universe in X-rays, the telescopes must be placed above the Earth’s atmosphere, on orbiting satellites (as described in section 5.2.1). This is because the Earth’s atmosphere is virtually opaque to such high energy radiation. In fact, this is lucky for us, as cosmic X-rays might otherwise be harmful to life on Earth.

The European Space Agency’s XMM-Newton X-ray telescope collects X-rays by the satellite’s three co-aligned telescope systems. Within each telescope, the X-rays pass into a set of barrel-shaped co-axial mirrors (in fact only a few of the actual 58 concentric mirrors are shown). After reflecting off the gold-plated mirrors at grazing angles of incidence, the now focused X-rays are collected at the other end of the 10-metre-long spacecraft where the imaging detectors and X-ray spectrographs sit.  

ACTIVITY: The animation below depicts how the European Space Agency’s XMM-Newton X-ray telescope collects these X-rays and converts them to useful information.

(credit: ESA)

ACTIVITY: The following video explains more about the XMM-Newton mission, how it got its name, and reports the first science results that were obtained.

(credit: ESA)