Dennis Mammana: Seeing the Solar System Go Online | Outside

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This week before sunrise, you should be able to spot all of the visible planets – Mercury, Venus, Mars, Jupiter, and Saturn – in order of their distance from the sun. A rarity indeed! (

There are plenty of celestial phenomena to excite stargazers, but few are as cool as the one you’ll be able to see over the next two weeks. Your only challenge will be to force yourself out before sunrise!

If so, and if you have a very low eastern horizon, you should be able to spot all of the visible planets—Mercury, Venus, Mars, Jupiter, and Saturn—in order of their distance from the sun. A rarity indeed!

During morning twilight over the next two weeks cast your gaze very low into the eastern sky. Here you will find Mercury, one of the most elusive planets because it never rises very high before the glare of the sun lights up the sky. At the top right is the bright planet Venus, which is rather hard to miss.

Follow these two worlds upward into the southeastern sky and you’ll encounter the red planet, Mars, as well as the much brighter gas giant, Jupiter. Continue the arc to the southern sky and you will find the last of these five visible planets: the ringed planet Saturn.

Some people might be alarmed to see the planets “aligned” in this way, but those who understand how our cosmos works know that the arc along which they appear is the geometric plane of our solar system – the path along which the most of the solar systems the bodies travel.

This is happening because of how our planetary family collapsed and flattened after the birth of the sun about 5 billion years ago; as a result, almost everything revolves around our parent star along this plane.

From within, we see this plane as a wide arc stretching across our sky; it represents the path along which the planets pass in front of the most distant stars. Astronomers call this the ‘ecliptic’ and although it is always in the sky, its position is only obvious when planets or the moon are present to plot it for us.

If you look at the sky for more than one morning, you will find that the waning gibbous moon comes into play on June 15, as it sets in the western sky at morning twilight. Over the next two weeks, watch it drift eastward, changing phases daily and passing each of the planets in turn as it orbits Earth.

This shouldn’t surprise you; it too is part of our solar system and follows the same path, although it seems to move away a little. This is because the moon’s orbit is inclined about five degrees to the plane of the ecliptic, so we sometimes see the moon appear above and sometimes below the general path of the planets.

Seeing five planets at once is pretty cool, but if you want an even bigger challenge and have a telescope and more experience, you might also be able to find the outermost planets, Uranus and Neptune, as well as two extremely weak dwarfs. planets, Eris and Pluto.

Yes, it’s pretty rare for all of these solar system bodies to appear in the same sky, so be sure to check it out. And while you’re there, don’t forget to notice another planet, but this one won’t appear in the sky!

— Dennis Mammana is an astronomy writer, author, speaker, and photographer working under the clear, dark skies of the Anza-Borrego Desert in outback San Diego County. Contact him at [email protected] and connect with him on Facebook: @dennismammana. Click here to read previous columns. The opinions expressed are his own.

Arline J. Mercier