Flickers and Shadows
More Ways to Find Planets
Since faint planets are hard to see next to bright stars, astronomers have had to come up with clever ways to unveil them. The Doppler technique—using spectral line shifts to trace the subtle dance of stars as planets tug on them—has been the most successful in the first fifteen years. But two other methods have also reached maturity—and are paying off handsomely. Both depend on finding chance alignments of celestial objects through brightness changes of stars.
The first technique exploits a remarkable property of gravity that Albert Einstein discovered: its ability to bend light, thus to magnify the brightness of a distant star temporarily when a nearer star happens to cross our line of ...