Week of April 17-23, 2016

What a wonderful assortment of celestial bodies we'll be able to see this week and next — if we head outdoors around midnight or so.

Around that time in the southeastern sky, look for the first appearance of the summertime stars and planets. The "star" of the show in that direction is Antares, the main star in the constellation of Scorpius, the scorpion.

Slightly to its east you'll notice two other brighter stars, but they aren't actually what they appear to be; they're the planets Mars and Saturn. Saturn is the planet with those glorious 3-D rings, while we know Mars as the Red Planet because of its reddish-orange glow.

The difference between stars and planets is that stars produce their own light, while planets shine by reflecting the light of our star (the sun). And, of course, stars are much farther away. Antares, for example, lies about 3,600 trillion miles away, so distant that its light takes some 600 years to reach us.

It's also a matter of size. Saturn is about 10 times larger than the Earth, and Mars is only half the size of our planet, but Antares would dwarf them both. In fact, if Antares were to replace the sun at the center of our solar system, its massive atmosphere would engulf the orbits of Mercury, Venus, Earth and Mars, and span much of the distance to Jupiter.

Now, if you recall enjoying Antares and Scorpius last summer and wonder why you didn't notice Saturn and Mars nearby at the time, that's OK. Remember, these are planets, and since they orbit the sun along with the Earth, we see them against different star patterns as we move about. It was for this very reason that the ancient Greeks called them "planetes," which means "wanderers." And if you keep an eye on them over the next few weeks or months, you'll see that's exactly what they appear to do.

Not only do the planets seem to drift among the more distant stars, but so, too, does the moon. The moon is our planet's natural satellite, and it orbits our world just about every 28 days. During its orbit, the moon is lit by sunlight from different angles, causing the moon phases we see throughout the month. Its orbit also causes its position to change in the sky.

And this lunar movement is something we'll be able to notice quite well next week. Fresh from its full-moon phase on April 22, the moon will begin crossing the late night and early morning sky throughout the next couple of weeks. If you're out late on the night of April 23, you may spot the moon to the west of the Mars-Saturn-Antares trio. Late on the night of April 25, it won't lie too far from its east.

The night between, however, is when the real display occurs. Be sure to check it out around midnight on April 24. You'll see all four celestial bodies appearing within just 10 degrees of each other in the southeastern sky.

If you miss this midnight sky show, don't worry — it will appear all night until the break of dawn on April 25.

See the celestial grouping in Scorpius late April.

Visit Dennis Mammana at www.dennismammana.com. To read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.