"What's your sign?"
Most everyone has heard this classic pick-up line in a bar or at a party. And almost everyone can answer the question. Whether you read your horoscope daily, weekly, monthly, only on New Years' day, or never - your sign is something you know. You may know the twelve signs are divided up among four elements: Earth, Water, Fire, and Air. You may also know the attributes assigned to each of the twelve zodiac symbols. For example: Taurus-the bull: is an Earth sign and exhibits strength, leadership, stubbornness. Pisces-the fish: is a Water sign and exhibits sensitivity, empathy, and are dreamers. Leo-the lion: is a Fire sign and a Leo exhibits strength, is charismatic, stands out in a crowd. Gemini-the Twins: is an Air sign and they exhibit an agile mind, are good communicators, seek out ideas/experiences. There are even "ages" where one sign dominates for a period of time. An Age is defined by which constellation is behind the sun on the spring equinox in the northern hemisphere (March 20). Today, we are in the Age of Pisces. In about 600 years, Aquarius will be the constellation behind the sun on the spring equinox and it will then be the Age of Aquarius (the song incorrectly tells us we are in it now). But what causes the ages to change with time?
Humans have been aware of the zodiac, the signs and astrology since Babylonians created them around 2500 years ago. Originally, they had 17 constellations assigned to their zodiac. This was simplified in their star catalogues to the 12 we have today. The zodiac sign was determined by which constellation was behind the sun during a specific period of time. As the Earth orbits the sun, the backdrop of stars and constellations behind the sun changes. Thus, the constellation behind the sun changes as well (about every 26-30 days). The Babylonians used this change in constellations to tell time and forecast the future (thus they were some of the first astrologer-astronomers).
But (and isn't there always a 'but' in science), the Earth does more than revolve about the sun, it also rotates about its axis. Earth's axis is tipped 23.5 degrees away from vertical. As the Earth rotates about its tilted axis other things affect its motion: gravity of the sun and moon pull on the planet; the Earth is not a perfect sphere, it is shaped like an egg or an oblate spheroid with a pronounced 'bulge' at the equator (caused by the rotating planet stacking up oceanic waters at the equator); the weight distribution of the continental plates versus ocean basins is not equal around the globe (if all the plates were bound together and all on one side of the planet - this would create a large, uneven weight distribution on one side, this occurred 375 to 175 million years ago when the supercontinent Pangea was in existence); and now we have the influence of climate change-melting glaciers and ice sheets which are raising sea levels and adding weight to the oceans. What do all these factors do to the spinning planet - they cause the rotational axis to be pushed and pulled or wobble. The wobble of the axis is called precession. Think of a top spinning about its axis: as its speed of rotation slows down the top starts to tilt away from vertical and the axis of rotation begins to wobble (inscribing an irregular circle) as it decelerates, until it loses its battle with gravity and falls over.
Precession causes the Earth's axis to slowly move away from a perfectly scribed-circle of rotation to a squiggly one, thus the Earth's axis points to a slightly different point in space over time. For example, our North Star is Polaris in the constellation Ursa Minor. But the North Star wasn't always Polaris because of rotational wobble. The Egyptians (about 3500 years ago) recognized Thuban in the constellation Draco as their North Star. If any have read our book - A Quantum Convergence - you know the protagonist used her knowledge of astronomy and the stars to determine 'when' she was. In her time, the North Star was Vega in the constellation Lyra, so she determined she was 13,000 years in the future having arrived in another part of the multiverse we exist in.
So what does Earth's wobbly rotation mean when answering the classic pick-up line next time you're in a bar or at a party? It means your answer will be incorrect. The sign you think you are is not the one you actually are. Maybe you were an Aries 2500 years ago in Babylonia but because of our wobbling Earth and precession through time you are a Pisces not Aries, as the Earth's precession has aligned the constellation Pisces behind the sun from March 21 to April 19.
And not to put too fine a point on the impact of astronomy on astrology, but another complication is not all twelve constellations which make up the signs of the Babylonian zodiac are the same size. So due to the difference in constellation size, the sun stays in front of the super large constellation Virgo twice as long as it does in front of Cancer. Whereas, poor little Scorpio only sits behind the sun for a week. Size does matter in astronomy.
And 12 is not enough, we must consider the illusive thirteenth sign, one we know little to nothing about? Is it not mentioned because 13 is an unlucky number? Or are you one who believes 13 is a lucky number and would want to know more? Ophiuchus is the 13th constellation along the path of the sun's orbit. Ophiuchus is translated from Ancient Greek to Serpent-bearer. Due to Earth's precession, those born under Sagittarius would actually be under the sign of Ophiuchus.
Today, astrology and astronomy share little to nothing in common. In fact, a practicer of one discipline may scoff at the other. But, 2500 years ago the two sciences were one and the same. Even in the 17th century those who were known to be great astronomers - Johannes Kepler and Galileo Galilei - practiced astrology and entertained friends with their predictions, they even created astrological charts to sell to supplement their income.
So whether you believe that the motion of the planets and constellations foretell the future or are simply amazing patterns in the sky, each of us was born under one of the constellations which make up our amazing universe. The universe is a vast, amazing, and mostly unknown place. So, keep looking up, you'll never be disappointed.
How do today's astronomers study the universe?
Today we use a collection of earth-bound telescopes, near-Earth orbiting platforms, and space-bound instruments to study the vastness of space around us and reach out to far distant edges of our universe. Many things are impacting these amazing, though incredibly expensive endeavors: light pollution, Star-link micro satellites, space debris, regional conflicts, and even clashes between the superpowers.
One such conflict between the US and China has halted the construction of CART - the China-Argentina Radio Telescope. This project, which is more than 90% complete, now lies in pieces in the desert at the foot of the Andes. This telescope would be a boon to studies of the electromagnetic 'whispers' of the distant cosmos and complement the studies of the earliest galaxies being studied by the James Webb Space Telescope. The Big Bang and the origins of our universe made a really big noise across various frequencies of the electromagnetic spectrum. We have mapped the microwave emissions from this event and know their distribution which helps understand the Big Bang and the events immediately after. But more is needed to understand the near-Bang events in the early universe.
CART will augment these other investigations. It is a purely scientific endeavor. It needs the last shipment of parts and equipment to be completed. But, the flow of equipment and engineers has stopped due to a stipulation on the $20billion of US funds pledged to Argentina. The stipulation: Argentina cut all strategic ties with China, including efforts to build "observational facilities".
Politics has once again stepped in the way of scientific achievement. And scientists may be able to look to edges of our universe but are hard pressed to fight the powers that be. (No Dollars if Telescope)