We have looked at local time which we use in the same way every day even though there are many variables affecting “real” time. This section takes a look at Space and time which is far more accurate than local time even though there are many more variables.
Space and Time…….continued from G1 Time
Moving into Astrophysics from “ordinary” time as we know it, into what is generally known as Cosmology, probably better known for its greatest fan – Stephen Hawking. One of Stephen’s last projects was to demonstrate that the universe was not flat, but round like a ball; light, sound, gravity and time flow as a river winds its way home to the sea, having tides, waves, and currents. Some days would be tranquil and calm, whereas the next days could be violent, turbulent with rips and rogue waves tossing planets and even stars around like flotsome, wreckage from destroyed celestial bodies in an endless sea.
While most people thought that it was a wacky idea and due to Stephen’s deteriorating health, it stirred deep thoughts I had puzzled over for a long time. Many of these abstract thoughts came together all in a rush of understanding that made my head spin as one after another fell into place.
NASA has for a long time believed that there should be an extra planet in our solar system, Planet X, but has been unable to pin it down, in spite of tantalizing glimpses, or shadows that kept their interest alive. As technology in astrophysics improved, rogue planets were appearing all over the universe, unattached to a star or solar system. They just seemed to drift aimlessly through space. Free, unattached and apparently avoiding capture by normal laws of gravity.
This is a dwarf star, old, alone, and drifting through space much like a rogue planet but here you can see the heat still being generated by nuclear fusion from its hydrogen-helium cycle. While some large planets such as Jupiter, Saturn and Uranus are gas giants the mechanism for their existence relies on gravitation, the pitch of their orbital spacing and the speed of rotation is what keeps them in place. You can see what I mean if you page up/down to the little graphic showing planetary precession (Time Part 1). You will also notice that an object from deep space comes into view every now and then and makes a slingshot orbit around the Sun back out into deep space. Most of these are comets that have wide eccentric orbits bringing them back years, sometimes thousands of years later.
You are probably saying “What has this to do with the price of eggs?”
Comets are often referred to as space snowballs releasing ice in the form of a vapour tail as they approach and leave the sun. Now, my question is; “Where does the water come from to form ice crystals in deep space?” and this is just the tip of the iceberg – excuse the pun; when it comes to the universal mystery of water.
Interesting. The tail always points away from the sun due to solar wind.
Even more interesting, water is the only element found in all forms: solid (ice) water (liquid) and gas (steam/vapour).
Photo by Johannes Plenio
Scientists have discovered a Super-Earth that is four times the mass of our planet and takes just 10.8 days to complete a whole year. According to the American space agency NASA, the exoplanet, called Ross 508 b, was discovered using a new infrared monitoring technique. It is located 37 light-years from us. The Super-Earth “skims in and out of its star’s habitable zone”. And it revolves around a red dwarf star called Ross 508, just like our Earth orbits the Sun.
Planetary motion while the solar system clings on for the ride.
This is called Planetary Precession.
Our Solar System is unique in the universe. To date, only one other star has been discovered with more than one planet in orbit around it and then it only has two in the “habitable zone”. Of course, what is habitable to us may be unhabitable to other alien species who we know from relatively recent archeology have, and perhaps still do, live on the earth. We will get into this more in the ancient history section coming up next.
If we were to build a spaceship for deep space travel it would have to replicate earth-type conditions for us to survive the trip. We would need an atmosphere, climate control, gravity and a means to measure time as if we were on earth to ensure continuity, health and sanity. We all know that without gravity we would just float off the planet until our body reached the point of balance known as the gravitational mass ratio. Once we got to that point of balance (probably 30 to 40,000 kilometers, above the earth’s surface) we would go into orbit. So, gravity is tied to mass – no mass, no gravity. Except……
Let’s just recap what we have learned so far: Mass, gravity, time, and vibration. All essential markers to existence.
Let’s stick with gravity for a while. Whilst we have said above “no mass – no gravity” there are exceptions. Gravitational waves.
Gravitational waves are invisible and can travel across the universe at the speed of light (186,000 miles per second) which makes for a severe disturbance to anything that gets in their way by stretching and squeezing anything in their path. Needless to say it takes a massive amount of energy to create such a wave. Examples are a star exploding asymmetrically such as a “Supernova”. A cornerstone star Betelgeuse, in the constellation of Orion, is a potential candidate and is about to collapse, if it hasn’t already. Another wave maker would be two large stars orbiting each other, or when two Black Holes orbit each other and eventually merge.
Photo by NASA of how mass bends space and consequently time. This is the basis of warp drive and passing the speed of light.
So gravity isn’t the innocent bystander we always thought it was, if we ever thought about it at all!
When I was in Grammar school, I got very interested in physics and astronomy, partially due to my dad buying me a 4 inch reflector telescope which I took up into the hills around Scarborough with minimal light pollution. Wow, even though it was small, looking into the Milky Way just blew me away and so I joined the British Astronomical Society at the age of 12. What surprised me was how many students didn’t understand the basics of gravity, particularly its variable velocity even at sea level. Gravity tells astronomers a lot about what is beyond our solar system as well as our own planet. If we were talking about sailing and boat design, we would look for the design’s center of gravity. In science, it is called the Barycenter because the middle of a star or planet is not necessarily its center but is offset by its Barycenter (center of gravity). This variable gives a star its “wobble” indicating that there is a gravitational draw externally pulling at the star, or a planet with moons. Very useful in astrophysics because it can tell us much more about the environment we are observing.
Sir Isaac Newton discovered the principle of gravity when an apple fell from the tree he was sitting under and hit him on the head! Actually, it didn’t hit him on the head, but was close enough to get his attention. Gravity has no mass, it is movement, hence a velocity that disperses over distance and time. At sea level on earth the velocity is 9.8 m/s/s and it is quite surprising how few people understand this basic mathematical equation. All it means is that in free fall the velocity increases by 9.8 meters every second, so after 2 seconds the velocity has gone up to 19.6 meters and so on.
Enough waffle about gravity for now.
One last aspect of the earth’s uniqueness (perhaps one and a half)
The earth’s magnetic field and van Allen belts.
Taken by Apollo 8 crewmember Bill Anders on December 24, 1968, at mission time 075:49:07 (16:40 UTC), while in orbit around the Moon, showing the Earth rising for the third time above the lunar horizon. The lunar horizon is approximately 780 kilometers from the spacecraft. Width of the photographed area at the lunar horizon is about 175 kilometers. The land mass visible just above the terminator line is west Africa. Note that this phenomenon is only visible to an observer in motion relative to the lunar surface. Because of the Moon’s synchronous rotation relative to the Earth (i.e., the same side of the Moon is always facing Earth), the Earth appears to be stationary (measured in anything less than a geological timescale) in the lunar “sky”. In order to observe the effect of Earth rising or setting over the Moon’s horizon, an observer must travel towards or away from the point on the lunar surface where the Earth is most directly overhead (centred in the sky). Otherwise, the Earth’s apparent motion/visible change will be limited to: 1. Growing larger/smaller as the orbital distance between the two bodies changes. 2. Slight apparent movement of the Earth due to the eccentricity of the Moon’s orbit, the effect being called libration. 3. Rotation of the Earth (the Moon’s rotation is synchronous relative to the Earth, the Earth’s rotation is not synchronous relative to the Moon). 4. Atmospheric & surface changes on Earth (i.e.: weather patterns, changing seasons, etc.). Two craters, visible on the image were named 8 Homeward and Anders’ Earthrise in honor of Apollo 8 by IAU in 2018.
- Public Domain
- File:NASA-Apollo8-Dec24-Earthrise.jpg
- Created: Taken on 24 December 1968, 15:40
Lighthouses shine to guide you home.
See more about lighthouses in the section for tall ships.