Have you ever wondering where the name of the days comes from? Why there are 7 days in a week? Why not 10 so it’s easier to count because almost all of our calculation is using decimal system or 10-based numbers?
“It’s a warm summer evening in ancient Greece…”, said Sheldon Cooper. You know the super genius Sheldon from The Big Bang Theory. You’ll laugh when you know what I’m taking about! But if you don’t, check this IMDB site, and start watching!
Anyway, every ancient civilization has their cosmic stories about stars, gods and goddesses, the universe and the creation of the human world. Back then, there were no enough light sources like what we have now. At night, the only sources of light were bonfire or maybe none at all. The sky was literary full of stars and all of the glorious things that the could be seen with the naked eyes. Bright and clear! Some of them became obsessed and started learning the sky object’s behavior in reference to the earth. It is really impressive to see the documents (not literary) painted on the cave walls, long tunnels inside the pyramid, coffins, tree barks or other mediums. Here is an example of the discovery:
In 185 CE, Chinese astronomers recorded the appearance of a bright star in the sky, and observed that it took about eight months to fade from the sky. It was observed to sparkle like a star and did not move across the heavens like a comet. These observations are consistent with the appearance of a supernova, and this is believed to be the oldest confirmed record of a supernova event by humankind. SN 185 may have also possibly been recorded in Roman literature, though no records have survived. – Source: Wikipedia
In the old days, people still believed that earth was the center of the universe. Ancient astronomers started creating their own heaven maps in conjunction to their location. After long observation, the sky maps became one of the civilization’s treasures because they could tell when the season starts, what to plant and when to start harvesting. That was the starting point of almanac and astrology which we know today. Almanac is predicting season and regional weather based on the stars position, where on other hand astrology is predicting someone’s life. The first one is considered to be accurate because of the cycle of the universe is pretty much the same from year to year, but the second one is more the pseudo-science which has no relation to the stars at all. Buy hey, it’s another topic of discussion and let’s not go there.
Once the ancient astronomers became the sky expert, they started noticing that some “stars” are more dynamic, active and exotic than others. Those “stars” are exclusive and so special! The ancient Greek calls them “the wanderers” or planetes (πλανήτης). Aha! That’s where the word planet originated from.
According to Greek, those planets are the sun and the moon, and five (5) special objects which are visible without using telescope or other tools. They are Mercury, Venus, Mars, Jupiter and Saturn. I think this one deserves another “aha” moment? Or eureka maybe? Anyway, the 7 majestic objects in the sky became natural wonders for the ancient civilization. Thus, it wouldn’t be a surprise at all to see when people started promoting them to represent the super-beings who take control the universe. In fact, those planets are in the sky, out of human reach physically and philosophically. The term of super-being is absolutely perfect, isn’t it? Each object is declared as god or goddess, and each day is dedicated to one super-being. Now you know that there are 7 days in a week! However, not all ancient civilizations have 7 gods or goddesses. Since the planet story (7 classical planets) were originated from ancient Greek and Roman civilization, it had a higher chance to reach a wider area during military events and trading routes compare to others.
What about name? This took hundred years to evolve. Let’s start with Greek first. Based on their observation, the days were sorted by the closest distance from the planet earth. Remember, in that time, they believed that earth was the center of the universe. So, the order was Moon, Mercury, Venus, Sun, Mars, Jupiter and Saturn. Well, not exactly accurate, but it was believed that way in that time.
When the Roman Empire spread around the region, there are many tradition transitions, from the original Greco-Roman to Gaelic-Irish and finally Germanic. The name of the day started mixing up and evolved to the base word of today’s name. There’s no accurate documentation when exactly the naming started, but historian predicted it was between 400AD and 7-8th century. Let’s take a look:
- Sunday: Sunnandæg meaning “Sun’s day”
- Monday: Mōnandæg meaning “Moon’s day”
- Tuesday: Tīwesdæg meaning “Tiw’s day, a one-handed god associated with single combat. The name is based on Latin dies Martis, “Day of Mars”.
- Wednesday: Wōdnesdæg meaning the day of the Germanic god Wodan. It is based on Latin dies Mercurii, “Day of Mercury.”
- Thursday: Þūnresdæg meaning ‘Þunor’s day’, thunder or its personification, the Norse god known in Modern English as Thor. Thor’s day corresponds to Latin dies Iovis or “Day of Jupiter”.
- Friday: Frīgedæg meaning the day of the Norse goddess Fríge. It is based on the Latin dies Veneris, “Day of Venus.”
- Saturday: Sæturnesdæg. In Latin it was dies Saturni, “Day of Saturn.”
That’s all for now. Hope you enjoy it
I got this from my friend’s Facebook wall:
In an MIT recruitment packet, there was a card of quotes with this: “If you’re the smartest person in the room, you’re in the wrong room.”
It has the similar meaning with the teapot and cup anecdote. When the cup is full, pouring tea is just a waste of time and material. This kind of attitude prevents someone to learn and grow.
Do we have second moon? Third? Or maybe more? Well, before we go there, let’s talk about asteroids first.
Simply said, asteroids are chunk of rocks or any astronomical objects other than planets, comets or man-made that orbits the sun. A Trojan asteroid is a minor object or natural satellite that shares an orbit with a planet. The interesting thing about this type of asteroid, it does not collide with the main planet because it orbits around the Lagrangian points (a location in space where the forces of their mutual gravitational attraction balance each other out).
That said, any objects that stay in the Lagrangian points will stay there and follow the movement (revolution) of the main planet around the sun. One of many Trojan asteroid is called Cruithne (discovered on October 10, 1986, by Duncan Waldron). The diameter is approximately 3.1 miles, and the closest approach to Earth is roughly about 7,500,000 miles. That’s pretty far from us!
Cruithne has a normal elliptic orbit around the Sun. Because Cruithne and Earth “follow” each other in their paths around the Sun, the period of revolution is the same as earth. One year on Cruithne is exactly same as one year on earth. What about on the moon? Same! This is why Cruithne is sometimes called “Earth’s second moon”.
Here’s few more technical excerpt:
Although Cruithne’s orbit is not thought to be stable over the long term, calculations by Wiegert and Innanen showed that it has probably been synchronized with Earth’s orbit for a long time. There is no danger of a collision with Earth for millions of years, if ever. Its orbital path and Earth’s do not cross, and its orbital plane is currently tilted to that of the Earth by 19.8°. Cruithne, having a maximum near-Earth magnitude of +15.8, is fainter than Pluto and would require at least a 12.5-inch (320 mm) reflecting telescope to be seen.
Due to a high orbital eccentricity, Cruithne’s distance from the Sun and orbital speed vary a lot more than the Earth’s, so from the Earth’s point of view Cruithne actually follows a kidney-bean-shaped horseshoe orbit ahead of the Earth, taking slightly less than one year to complete a circuit of the “bean”. Because it takes slightly less than a year, the Earth “falls behind” the bean a little more each year, and so from our point of view, the circuit is not quite closed, but rather like a spiral loop that moves slowly away from the Earth.
After many years, the Earth will have fallen so far behind that Cruithne will then actually be “catching up” on the Earth from “behind”. When it eventually does catch up, Cruithne will make a series of annual close approaches to the Earth and gravitationally exchange orbital energy with Earth; this will alter Cruithne’s orbit by a little over half a million kilometres—while Earth’s orbit is altered by about 1.3 centimetres (0.51 in)—so that its period of revolution around the Sun will then become slightly more than a year. The kidney bean will then start to migrate away from the Earth again in the opposite direction – instead of the Earth “falling behind” the bean, the Earth is “pulling away from” the bean. The next such series of close approaches will be centred on the year 2292 – in July of that year, Cruithne will approach Earth to about 12,500,000 kilometres (7,800,000 mi).
Ok. So now you know! There are many objects in Lagrangian points that have been sitting there for months, years or million of years. This kind of stories or articles are available publicly. However, only people who are interested know about this aware and understand. The rest of people probably don’t care or not even want to know. It’s OK. There’s nothing wrong about that and it’s perfectly normal. Don’t get scared or cause mass panic if someone, groups or media start sending a rumor about second moons, planet nubiru, super black hole or other space comic stories. Please do research a little bit. Be part of the solution, not the panic wave.
Hope it helps. Cheers…
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Even if the camera’s weight is so light, it affects the rocket’s balance. Center of gravity, trust point, rotation behavior (centrifugal point) and lift-off characteristics. I was kind of nervous if the rocket goes wild. Therefore, I decided to use the smallest engine I have.
B6-4 engine! The first letter is the rocket class. For example, the B6 engine delivers 6N impulse trust. The smallest is 1/8A, which is really tiny. Up to class Z which is used for Space Shuttle booster. The last number is how many seconds delay before the ejection firing starts. The delay is useful to let the rocket cruises in a specific altitude for preparing the next stage or deploy a parachute.
Let’s cut it short. Below are the video links. By the way, I forgot to set the date time for the camera, so it’s showing year 2008. Yeah, it’s embarrassing but I learn from it. Won’t happen next time. Enjoy!
- B6-4 ground: http://youtu.be/cYSdKpHK0xc
- B6-4 on-board: http://youtu.be/LMr2nwhfawY
- C6-5 ground: http://youtu.be/x25OSgVnd0Q
- C6-5 on-board: http://youtu.be/XqOAePOtafo