<P> By looking at the wiggles of an interferogram using a Fourier - Transform - Spectrometer, enhanced sensitivity could be obtained in order to detect faint signals from Earth - like planets . </P> <P> Disks of space dust (debris disks) surround many stars . The dust can be detected because it absorbs ordinary starlight and re-emits it as infrared radiation . Even if the dust particles have a total mass well less than that of Earth, they can still have a large enough total surface area that they outshine their parent star in infrared wavelengths . </P> <P> The Hubble Space Telescope is capable of observing dust disks with its NICMOS (Near Infrared Camera and Multi-Object Spectrometer) instrument . Even better images have now been taken by its sister instrument, the Spitzer Space Telescope, and by the European Space Agency's Herschel Space Observatory, which can see far deeper into infrared wavelengths than the Hubble can . Dust disks have now been found around more than 15% of nearby sunlike stars . </P> <P> The dust is thought to be generated by collisions among comets and asteroids . Radiation pressure from the star will push the dust particles away into interstellar space over a relatively short timescale . Therefore, the detection of dust indicates continual replenishment by new collisions, and provides strong indirect evidence of the presence of small bodies like comets and asteroids that orbit the parent star . For example, the dust disk around the star tau Ceti indicates that that star has a population of objects analogous to our own Solar System's Kuiper Belt, but at least ten times thicker . </P>

Describe how exoplanets are discovered by measuring stellar radial velocities quizlet