Around 4.5 billion years ago our solar system was nothing more than a big cloud of gas and dust, not much different from the Orion Nebula (Messier 42) that we enjoy looking at with our backyard telescopes every winter. Composed mostly of hydrogen, the cloud coalesced over billions of years till a catalyst —most likely the shock wave from a nearby star exploding as a supernova — jolted the cloud into a spin and it began collapsing in on itself. The dense center of the nebula became our sun, the cloud flattened into a disk, and clumps of gas farther out spun up into the gas giants that dominate the outer solar system.
Scattered between these giants were pockets of primordial dust left over from the very first stars and planets that populated our universe. This dust collided and stuck together to form larger and larger rocky bodies, eventually the size of small planets called planetesimals. Dozens or possibly hundreds of these baby planets collided over hundreds of millions of years, forming the rocky planets of our solar system today and scattering debris across the system as asteroids, comets and moons.
From the initial shock that jolted our solar system into motion, everything continued to spin. Through eons of chaos and disorder, the rotation of the planets, moons, asteroids, comets, even the sun itself persisted.
The flattened disk that was the nursery for the birth of planets maintained a consistent path through space, which today we call the ecliptic. The ecliptic is the superhighway on which the sun and planets travel across our sky. Despite the violent early days of the solar system and the catastrophic collisions of protoplanets, none of the eight major planets ever strayed more than a few degrees from this original orbital plane. So we can look out and quickly identify the planets wandering against the backdrop of apparently motionless stars. For this reason the word ‘planet’ comes from the Greek planete, or ‘wanderer.’
Early in the morning of June 3 the wanderers will come together for a relatively rare celestial alignment. In the hour before sunrise at 5:17am, look to the east to see up to six planets followed closely by the sun. Starting to the southeast, Saturn will shine brightly. As you move down to the east you’ll pass Neptune under the belly of Pisces, Mars glowing red near the crescent moon, followed by Uranus, then Jupiter peeking over the horizon. Venus may be visible in the best observing situations, but Mercury will certainly be obscured by the rising sun.
Wishing you clear skies as you observe this parade of planets and throughout the month of June!
If you would like to learn more about the sky, telescopes, or socialize with other amateur astronomers, visit us at prescottastronomyclub.org or Facebook @PrescottAstronomyClub to find the next star party, Star Talk, or event.
Adam England is the owner of Manzanita Financial and moonlights as an amateur astronomer, writer, and interplanetary conquest consultant. Follow his rants and exploits on Twitter @AZSalesman or at Facebook.com/insuredbyadam.
