What practical value did astronomy offer to ancient civilizations?
It helped them keep track of time and seasons, and it was used by some cultures for navigation.
Only a few ancient cultures were good at predicting eclipses, and eclipses play a little practical role in civilization.
Astronomy was used in various ways by different ancient people groups, and to an extent, is still used the same way today. Navigation by stars allowed many peoples, particularly the Polynesian explorers, to travel long distances between islands with nothing but the sun and stars to guide them. Other groups, such as the Egyptians, timed the planting of their crops to the appearance and position of specific stars. In modern times these skills in astronomy are less used than previously however many people are still able to navigate at night by using the stars to guide them.
<h2>What is the difference between astronomy and astrology?</h2>
Astrology and astronomy are concepts related to the universe. In the early ages, astrology and astronomy were terms used indistinguishably. These two concepts were separated gradually from the 17th century onwards until they were declared to be entirely independent of each other.
Astronomy is the mathematics of celestial phenomena. Astrology - far from being "retarded nonsense" is one of the oldest organized bodies of knowledge in the world. One that is across many cultures, and has been existent for more than 2,000 years in some form.
Astrology is concerned with meaning, not just measurement.
Astrology, if studied with an open mind (rather than glibly dismissed) yields incredible insight and understanding about oneself, and life in general.
Astrology is not a "superstition" - there is no valid reason to tag it with that, other than ignorance. I welcome open-minded inquiry into astrology, and I love science and all that science, including astronomy, has achieved. I have little time for superficial dismissal of a topic with such a long and respected pedigree. It is all too easy to arrogantly dismiss something without the slightest bit of understanding of what you are actually dismissing.
Astronomy is hard science that studies the whole of the universe outside the earth’s atmosphere. Every event in the universe is recorded and studied by astronomers. planets, stars, galaxies, and their relationship to each other. Starstuff, as Carl Sagan used to say is what everything is about. His popular television program Cosmos brought his fascination with astronomy into the living rooms of people everywhere.
Astrology is a popular diversion for most people who study the planets and the stars in relation to their movements to each other and the effect they have on events and the doings of individuals according to when they were born. Adolph Hitler believed that the stars guided his destiny and that of the German people. Ronald Reagan, the late president of the U.S., famously followed astrology charts ( His wife Nancy was the power behind the president and believed everything was preordained by the stars).
What did Tycho do that advanced astronomy significantly?
He first used the telescope to make extensive astronomical observations. He determined that the planets orbit the Sun in elliptical orbits. He proposed some simple laws that govern the motion of the planets and other objects.
Tycho Brahe Danish astronomer whose work in developing astronomical instruments and in measuring and fixing the positions of stars paved the way for future discoveries. His observations—the most accurate possible before the invention of the telescope—included a comprehensive study of the solar system and accurate positions of more than 777 fixed stars.
Brahe made careful observations of a comet in 1577. By measuring the parallax for the comet, he was able to show that the comet was further away than the Moon. This contradicted the teachings of Aristotle, who had held that comets were atmospheric phenomena ("gases burning in the atmosphere" was a common explanation among Aristotelians). As for the case of the supernova, comets represented an obvious change in a celestial sphere that was supposed to be unchanging; furthermore, it was very difficult to ascribe uniform circular motion to a comet.
Why is a light-year a more useful measurement in astronomy than a meter is?
The enormous size of the galaxy and universe necessitates a much larger unit of measure than is provided by the meter. If meters were the standard unit of measure, numeric representations of distances between celestial bodies would be so large as to be impractical. Interstellar distances are so vast that our unit of length called kilometers becomes inappropriate. It is already small even to measure the largest distances in the Solar System! That’s why for many things inside the Solar System, we use the unit of length called AU, Astronomical Unit, which is equal to the average distance from Earth to the Sun, 150 million km.
Measuring in miles or kilometers at an astronomical scale would be extremely cumbersome and impractical. Starting in our cosmic neighborhood, the closest star-forming region to us, the Orion Nebula, is a short 7,861,000,000,000,000 miles away, or more simply, 1,300 light-years away. The center of our galaxy is about 27,000 light-years away. The nearest spiral galaxy to ours, the Andromeda galaxy, is 2.5 million light-years away. Some of the most distant galaxies we can see are billions of light-years from us.
Measuring in light-years also allows astronomers to determine how far back in time they are viewing. Because light takes time to travel to our eyes, everything we view in the night sky has already happened. In other words, when you observe something 1 light-year away, you see it as it appeared exactly one year ago. We see the Andromeda galaxy as it appeared 2.5 million years ago. The most distant object we can see, the cosmic microwave background, is also our oldest view of the universe, occurring just after the Big Bang some 13.8 billion years ago.