Tuesday, July 01, 2008

War, Change and the Little King

Planets and Stars Gather:
War, Change and the Little King
by Dave Adalian

Look to the west tonight between sunset and 10 o’clock and you’ll find a pair of planets and a bright star artfully grouped just above the reddened horizon.

All year long, the ringed planet glided slowly through Leo the Lion while angry red Mars sat nearby in Cancer the Crab. As summer reaches its height, the War God is on the move, slipping into the lion’s den to join Saturn, Roman god of change and growth.

As the trio stands now you’ll find ruddy Mars between the brightest star in Leo, brilliant white Regulus, on Mars’ right and yellowish Saturn to its left. Although low to the horizon, the Bringer of Change still outshines almost everything else in the sky.

Of the three, Mars is smallest and closest, only 4,000 miles wide at its widest, compared to Saturn’s nearly 75,000-mile girth (or 150,000 miles if you count the rings, which are the largest structure in the Solar System after Sol).

But, Mars, Saturn and even Sol are dwarfed by Regulus, which carries a bulk three and a half times the sun’s. It’s about that many times as wide in the middle, too. Regulus -- the star’s name means “little king” -- also spins faster than the sun. Sol turns once each month; Regulus turns once every 16 hours, almost fast enough to fling the star apart, but not quite. It is fast enough to make Regulus oblate, meaning it’s squashed flat like a cosmic M&M candy.

Tonight, Mars will be closer to Regulus than Saturn, but the two planets are headed for a very close encounter on July 9-10, with Mars seeming to move steadily in Saturn’s direction during the next seven days. All during the week, the trio will make for spectacular viewing, and the show gets even better on the nights of July 5 and 6 when the conjoined planets and Regulus are met by a young crescent moon, which will be below the trio the first night and beside it the second.

This event effectively marks the end of the Saturn viewing season, and Mars and Saturn won’t be this close again until 2022, but planet hunters take heart: While Saturn and Mars are leaving the sky, Jupiter, Saturn’s son and king of the planets, is coming into its best, appearing as the brightest thing in the sky. Find it by looking southwest after sundown.


This column originally appeared in the Visalia (Calif.) Times-Delta and the Tulare (Calif.) Advance-Register in July of 2008.