rjvanderbei

Last Tuesday, Venus passed directly between the Earth and the Sun.   Such transits are rare events.  They come in eight-year-apart pairs but the pairs are separated by more than one hundred years.   The next transit event will not take place until 2117.  So, astronomers, both professional and amateur, eagerly awaited (and prepared for)...

Currently, Mercury, Venus, Jupiter, and the Moon are in the western sky at and after sunset.   This is a picture I took at 5:45pm on February 27, 2012.   The Moon is obvious in the picture.  Venus and Jupiter are small specks of light that are marked in the photograph.   Mercury is not...

A popular explanation for the Star of Bethlehem is that it was actually a conjunction of Jupiter and Venus that presumably occurred on June 17, 2BC  (see bethlehemstar.net).  In other words, in the evening hours of that day, Jupiter and Venus appeared so close together in the sky to observers in the middle east that...

Our planet Earth orbits the Sun once every year whereas it takes Jupiter about twelve years to complete one orbit.  This means that once every thirteen months Earth catches up to Jupiter and passes it in this planetary race around the Sun.   When Earth “passes” Jupiter, we say that Jupiter is at “opposition”.  This...

Text by J. Richard Gott The 2011 Nobel Prize in Physics has been awarded to Adam Riess, Brian Schmidt, and Saul Perlmutter for their discovery of the accelerating expansion of the universe.  It is one of the times when astronomers have won the Nobel Prize in Physics.  It is perhaps the most important scientific discovery...

It takes Jupiter about twelve years to orbit the Sun just once. We, here on Earth, are of course closer to the Sun and go around much faster—once per year. So, every 13 months we “lap” Jupiter. The next lapping event, which astronomers call “opposition”, will be on October 29th of this year. On that...

A friend of mine has a popular astronomer’s toy—a gizmo called a Sky Quality Meter. It measures light pollution. Point it at the nighttime sky and it tells you how bright the sky is—in magnitudes per square arcsecond. Where he lives, the skies are pretty dark at night (at least for New Jersey). His gizmo...

The Milky Way, with its myriad of stars and nebulae, rules the summer night skies. The core of the Milky Way lies in the constellation Sagittarius.  For those of us observing from mid-latitudes in the northern hemisphere, Sagittarius never rises high in the sky.  At its best, it is seen low in the south during summer...

Who would have imagined that just a few weeks after I blogged about the 2005 supernova in the Whirlpool Galaxy, we’d be treated to a second supernova in the same galaxy.   It’s quite unusual to have two in the same nearby galaxy in such a short time. The animation above was made from three...

One of the brightest nebulae of the summer night sky is the Ring Nebula.  It was discovered by Antoine Darquier de Pellepoix in 1779  and independently rediscovered just days later by Charles Messier.  The nebula is also known as M57 as it is the 57th object in Messier’s list of non-comets. As shown in the...

by Robert J. Vanderbei Jupiter, Venus, Mercury, and Mars have been gracing the predawn eastern sky in recent weeks. So far I have missed out on seeing this nice conjunction due to a combination of bad weather on the East Coast and an inability to get myself out of bed before sunrise. But all is...

by Robert J. Vanderbei Our sun is just one of hundreds of billions of stars in our galaxy, the Milky Way. A galaxy is an interesting thing. At the center of most large galaxies is a supermassive black hole. Many galaxies, such as our own, have spiral arms, places where the density of the stars...

by Robert J. Vanderbei Last Thursday the skies were clear in New Jersey and winds were not quite calm but manageable. I took the opportunity to grab a picture of the open star cluster called Messier 46 (M46) using my four-inch refractor telescope and my (monochrome) StarlightXpress CCD camera. This cluster passes directly overhead for...

by Robert J. Vanderbei Recently NASA’s Wide-field Infrared Survey Explorer (WISE) space telescope discovered an interesting asteroid named 2010 SO16. The asteroid is in a so-called “horseshoe” orbit with respect to Earth. Essentially that means the asteroid is in the same orbit as Earth but, at the moment, it trails us in our yearlong journey...

by Robert J. Vanderbei April is galaxy month. The arc of the Milky Way—our home galaxy—dominates the summer and winter nighttime skies. But in fall and spring, depending on the time of night, the Milky Way is usually seen making a ring around the horizon. For example, at midnight on April 15 the Milky Way...