Author Archives: Lisa R. Johnston

Einstein Rings

When you drop a piano on a cartoon character's head, what does he see? Stars, right? But what happens when you drop an ambitious sky survey attempting to map more than 100 million celestial objects on astronomers' desks? They see rings! Eight new Einstein "rings" have been discovered in the Sloan Digital Sky Survey...

Andromeda’s Black Hole Surrounded by Young Stars

It's no secret that supermassive black holes are thought to dwell in the centers of most galaxies, but what might be less well known is that only two black holes have been directly proven to exist under there. Now, thanks to some blue stars in a very unlikely place, make that three. The Andromeda...

Tycho’s Supernova Companion Discovered

On November 11, 1572, Tycho Brahe noted the appearance of a bright new star in the constellation Cassiopeia. This startling sight challenged the popular Aristotelian view of an unchanging heavens and perhaps even contributed to the opening scene of Shakespeare's Hamlet. Today we recognize this "new star" as the most recent of only two...

New Class of Low-luminosity GRBs

Gamma-ray bursts (GRBs) are becoming well-known for their frequent shots of high-energy in the deepest corners of space, many billions of light-years away. But now astronomers are beginning to think that these mega-explosions are going off all around us — we just can't see most of them. On December 3, 2003 the European Space...

Does Clarissa Have a Moon?

In spite of recent indications that asteroid 302 Clarissa has a moon circling around it, evidence now suggests that the object may be alone in the cosmos after all. On June 24th, four observers in the northeastern United States watched as the asteroid occulted the star SAO 118999. Astronomers predicted that the magnitude 9.6...

Gravity Probe B Puts General Relativity to the Test

It took nearly 90 years of theory, 40 years of engineering, and 10 years of lobbying to keep it alive — but yesterday scientists at Stanford University and NASA finally saw Gravity Probe B (GP-B) take flight to carry out the most accurate test yet of Einstein's general theory of relativity. The satellite was...