Latest / Star Trails: From Backyard Astronomy to Cosmic Wonder / Dark Skies and Dazzling Sights: Summer’s Celestial Fireworks
Transcript
- Welcome back to Star Trails! I’m Drew, your guide to the night sky. This week, we’re diving into the celestial fireworks visible from June 30th to July 6th, 2024, and later in the episode, we’ll explore the backward dance of the planets, known as retrograde motion. So grab your telescopes or binoculars, and a comfortable chair, and let’s explore what the cosmos has in store for us! This week the moon will transition from a waning crescent phase to a new moon phase. Here’s what you can expect during this period: At the start of the week the moon will be in its waning crescent phase. This phase is characterized by a thin crescent shape visible in the early morning sky before dawn. As the week progresses, the waning crescent continues to shrink, becoming thinner and closer to the horizon each morning. By July 4, the moon will be barely visible, rising just before sunrise and offering a sliver of light in the pre-dawn sky. The new moon occurs on July 6. During this phase, the moon is positioned between the Earth and the sun, making it nearly invisible in the night sky. The absence of the moon's light creates the darkest skies of the month, perfect for viewing stars, constellations, and deep sky objects. It also marks the beginning of a new lunar cycle, with the moon starting to transition into its waxing phases in the days following. You’ll need to be an early riser to catch most of the visible planets this week, with Mars and Saturn both putting on a show in the morning hours. Mars will be a prominent feature in the eastern early morning sky, shining at a magnitude of 1. It will be located in the constellation Aries, rising about three hours before sunrise. Mars will be relatively high in the sky, making the red planet easier to spot with the naked eye. For a special treat, get up early on the morning of July 2, when, in the pre-dawn hours, you’ll be able to spot Mars cozying up with the slender crescent moon, which will be just to the right of the Pleiades. Look just below the Pleiades to spot Jupiter. Clocking in at a bright -1.8 magnitude, Jupiter will start the week rising about two hours before sunrise in the constellation Taurus. Look for it low on the eastern horizon before dawn. Jupiter’s visibility will improve as the week progresses, climbing higher in the sky each morning Saturn will also be visible during the early morning hours. It will rise around midnight in the constellation Aquarius. By dawn, Saturn will be high in the southern sky. As I’ve mentioned before, Saturn’s rings are in the midst of a ring-plane crossing, which means they are nearly in an edge-on orientation to Earth. This means the rings look thinner than usual when viewed in a telescope. Mercury will be visible low on the western horizon in the evening twilight. Our smallest planet will be shining at magnitude 0.6, making it a bit challenging to spot without binoculars due to its proximity to the horizon and the Sun's glare. Venus will not be visible during this week as it is too close to the Sun. Both Uranus and Neptune will be visible in the early morning hours. Uranus will be located in Taurus and will be visible with binoculars. Neptune, located in the constellation Pisces, rises a few hours earlier, but will require a telescope to see owing to its faintness and distance. Let’s continue our tour of the summer constellations and learn a little bit about their lore. This week I’ve selected three animals of the sky: The Serpent, the Dolphin, and the Sea Goat. Serpens is a unique and fascinating constellation that is divided into two distinct parts: Serpens Caput (the Serpent's Head) and Serpens Cauda (the Serpent's Tail). It is the only constellation split into two non-contiguous areas by another constellation, Ophiuchus, the Serpent Bearer. In Greek mythology, Serpens represents the serpent held by Asclepius, the god of medicine, who used the snake's venom for healing and its regenerative abilities as a symbol of rebirth and renewal. Among the notable objects in Serpens is M16, the Eagle Nebula, which contains the famous Pillars of Creation. These towering columns of gas and dust are stellar nurseries where new stars are being born. The Eagle Nebula is located in Serpens Cauda and is about 7,000 light-years away from Earth. Additionally, Serpens Caput houses the globular cluster M5, which can be seen with binoculars or a small telescope. Delphinus, or the Dolphin, is a small and charming constellation that is easily recognizable by its distinctive kite-shaped pattern. According to Greek mythology, Delphinus represents the dolphin sent by Poseidon to find the sea nymph Amphitrite, whom he wanted to marry. Another myth tells the story of the musician Arion, who was saved by a dolphin sent by the gods when he was thrown overboard by pirates. Despite its small size, Delphinus contains several interesting objects. One of the highlights is Gamma Delphini, a beautiful double star system that can be observed with small telescopes. The two stars, one yellow and one blue, create a striking contrast. Additionally, Delphinus is home to the planetary nebula NGC 6891, a planetary nebula about 7,200 light years away. It appears as a small, faint ring with a central star visible through medium-sized scopes. It’s also home to NGC 6905, the Blue Flash Nebula. This object is a planetary nebula known for its blue color due to ionized oxygen, it is visible with medium to large telescopes. Capricornus, known as the Sea Goat, is a zodiac constellation that represents a creature with the front half of a goat and the tail of a fish. In Greek mythology, it is associated with the god Pan, who transformed himself into a sea goat to escape the monster Typhon. Capricornus is one of the oldest constellations, with roots in Babylonian and Sumerian astronomy. Capricornus is relatively faint, but it contains several interesting objects. The brightest star in the constellation is Delta Capricorni, which is a multiple star system located about 39 light-years from Earth. Another notable object is the globular cluster M30, which can be seen with binoculars or a small telescope. With the darkness provided by the New Moon, you’ll have better luck catching these fainter objects. Some classic deep sky favorites are still above, including The Great Hercules Cluster (M13). Located in the constellation Hercules, this globular cluster is a must-see. It’s visible with binoculars and even better through a telescope, showing off thousands of stars packed tightly together. Look for The Ring Nebula (M57) in Lyra. This planetary nebula is a beautiful sight through a telescope, appearing as a small ring of light. And finally, one of my favorites, the Andromeda Galaxy (M31) rises late in the night. Andromeda is the closest spiral galaxy to our Milky Way and can be seen as a faint smudge with the naked eye under dark skies. After a short break we’ll return to discuss an early mystery of astronomy – retrograde motion, the backwards dance of the planets. Stay with us. [RSS.com ad] Welcome back. Today, we're exploring the retrograde motion of planets. It's a celestial ballet that puzzled astronomers and philosophers for millennia. So, let's step onto the cosmic dance floor and discover why sometimes, planets seem to change their minds and waltz backward across the sky. To start, imagine you're standing on a carousel. As it spins, you look out and see another carousel moving alongside yours. Sometimes, as your carousel speeds up or slows down, it might appear as though the other carousel has stopped or is moving backward. This illusion is similar to what we observe with the planets in our solar system, a phenomenon known as retrograde motion. The ancient astronomers observed this backward dance with great interest, but it was a puzzle that wasn't fully solved until the time of Copernicus and later, Kepler. Early astronomers believed in a geocentric model, where Earth was the center of the universe. However, this model struggled to accurately explain the retrograde motion. It wasn't until the heliocentric model gained acceptance, with the Sun at the center, that the pieces began to fall into place. Retrograde motion occurs from our perspective here on Earth, due to our position within the solar system and how we orbit the Sun relative to other planets. When Earth overtakes a planet in its orbit, or vice versa, the planet appears to move backward against the backdrop of stars. This is purely an optical illusion, as planets do not physically change direction. The inner planets, Mercury and Venus, show retrograde motion when they are at inferior conjunction, passing between Earth and the Sun. For the outer planets, like Mars, Jupiter, and Saturn, retrograde motion occurs as Earth, on its faster orbit, passes them. This cosmic dance is not random but a regular part of the planets' orbits, predictable and consistent in its timing. If you’ve ever read your horoscope, perhaps you’ve seen a reference to a certain planet being in retrograde. In astrology, retrograde motion holds profound significance, often associated with periods of reflection and reevaluation. When a planet enters retrograde, astrologers believe it signals a time to pause and reconsider aspects of life related to the planet's influence. For instance, Mercury retrograde is famously linked with communication mishaps and technological snags, prompting individuals to review their methods of connection and information exchange. Similarly, Venus retrograde might encourage a reassessment of relationships and values, while Mars retrograde could be a period for rethinking one’s approach to conflict and assertiveness. These astrological periods are viewed not as times to fear, but as opportunities for inner growth and recalibration, offering a chance to rectify past mistakes and realign with one’s deeper goals and desires. There are currently three planets in retrograde. Saturn entered retrograde just days ago on June 29 and will be in that state until November. Neptune will enter retrograde this week on July 2, ending in December. Pluto, while not considered a planet anymore (It will always be a planet to me dammit!), entered retrograde on May 2, and will exit in October. So, what does this mean for us, the stargazers? Observing retrograde motion connects us directly to the history of astronomy, reminding us of our quest to understand our place in the universe. It's an example of how movement, perspective, and the laws of physics combine to create the celestial ballet we observe in the night sky. That’s all for this week’s episode of Star Trails. Before you go, I invite you to check out our weekly e-mail newsletter on Substack, where you can receive night sky reports and astronomy news that we don’t always mention on the podcast. It’s completely free, and a great supplement to the podcast. We’re also on Mastodon @star_trails and we’d love to hear from you. I’ll include links to both services in the show notes. Also, remember our website, startrails.show, where you can find all our episodes, including transcripts. Until next time, keep looking up and clear skies!