Try to convince sweltering Washingtonians that Earth is now the farthest it will travel from the sun this year. Well, it is.
On or about July 4 every year, the sun reaches aphelion -- at 94.5 million miles, the greatest distance between here and our solar system's burning ball of hydrogen and helium. The average distance is 93 million miles.
Our closest approach -- called perihelion -- occurs early in the year, always around Jan. 4, when Earth closes the gap to 91.5 million miles.
It might seem paradoxical that when Earth nears the sun the weather is cold in the northern hemisphere, and that when Earth moves farther away, the swimming pools open. Seasonal changes occur because our home planet tilts to the sun. As Earth travels its elliptical orbit, it remains at a 23-degree angle so that the summertime northern hemisphere points toward the sun and, six months later, the summertime southern hemisphere is directed toward the sun.
But on to this month's visible phenomenon. Watch celestial fireworks tomorrow morning and many mornings to come by catching the brilliant glow of Venus in the eastern sky. Venus will be sitting just above the horizon outshining everything else. To pick Venus from the starry crowd, find the object that looks like a headlight moving very slowly.
Currently at the ultra-bright -3.9 magnitude, Venus prepares for a rendezvous with the moon and Jupiter next month. Although Jupiter is not visible right now, next month it will have its closest observable conjunction with Venus in 41 years. The next good observable conjunction after that will be in the year 2082.
Crossing the southern sky, Saturn slowly turns into an evening object. This will be the best view of it offered this year. Finding Saturn may be tricky in the summer haze and light pollution, however. Look high in the south to find the constellation Aquila; 20 degrees below that constellation sits Saturn.
On July 14, Saturn is in opposition and the earth stands exactly between it and the sun. In 1988, the slow-moving planet reached its aphelion; it will not get to perihelion until 2003. Since the planet is bright enough to see with the unaided eye, at zero magnitude, go out to watch. And its rings are turned well enough to see in a moderately strong telescope.
Mars climbs above the eastern horizon during the late-night talk shows this month. It moves half as fast around the sun as Earth, and it doesn't celebrate seasonal change as often. Aside from the planetary perihelions and aphelions, comets also move around the sun. Current predictions for the newly discovered Comet Levy indicate that it will be bright enough for the naked eye in August. The comet's estimated luminosity is between eighth and ninth magnitude now, according to the International Astronomical Union in Cambridge, Mass. The brightness of Levy is predicted to be at 3.5 magnitude late next month. At that time, it will be about 40 million miles from Earth.
Geoff Chester of the Air and Space museum says the comet might be a good object to see later this summer. It is "a tad brighter than predictions," he says. "It is a very bright, condensed object. This bodes well for predictions." Comet Levy passes perihelion, or its closest nudge to the sun, late in October.
July 7 -- Computer-chip technology now makes it possible for telescopes in major cities to cut through the sky's grime and find stars. Richard Schmidt, an astronomer at the Naval Observatory, explains how he uses this technological marvel to photograph galaxies, quasars and comets. Einstein Planetarium at the Air and Space Museum. 9:30 a.m. Free.
July 28 -- Take a long, closer look at the moon, Saturn, a few nebulae and Comet Levy at Sky Meadow State Park, near Paris, Va. 8:30 p.m. Free.