In a recent post we demonstrated using the Newton’s cannon thought experiment that:
ISS and other satellites are always falling, but they are falling in Orbit
And this applies to planetary bodies too: Earth is always trying to fall into the sun, but it keeps falling in an orbit instead
But where did the initial velocity for the earth come from ?
Well, to answer that question one needs to go back 4.6 Billion years ago and look at the formation of the solar system.
And if you like numerical simulation and are wondering how could a spinning cloud of gas eventually form planets, take a look at the following video and its source paper.
JunoCam
is a visible-light camera/telescope placed on the Juno Jupiter Orbiter.
But the cool part about this is that it was primarily put on board the
orbiter primarily for public science and outreach.
If you are
an amateur astronomer and also interested in image processing, you have
full access to all the raw images taken by the orbiter (check link).
Summary: Around 1997, there were three great storms named FA, DE and BC on Jupiter. Then DE got jealous that BC was getting all the attention from Earthlings and went on a vortex attack ,destroyed it and ascended the throne as BE.
When FA came to know about what had happened, it summoned all the gases and went on a full out attack on BE to become BA
Now if you were like me, this might come to you as a huge surprise because whenever one thinks about Jupiter one is not used to visualizing it with rings around it, but rather as a huge gas giant.
The rings are not prominent
Unlike Saturn’ rings which are bright, the discovery of Jupiter’s wings had to wait till 1979.
This is so because the rings are faint and are only visible only when viewed behind Jupiter and lit up by the sun.
How are they formed ?
Jupiter’s rings are formed from dust particles hurled up by micro-meteor
impacts on Jupiter’s small inner moons and captured into orbit.
If the
impacts on the moons were any larger, then the larger dust thrown up
would be pulled back down to the moon’s surface by gravity (meaning that the dust would not have enough velocity to escape the surface).
The main and halo rings consist of dust ejected from the moonsMetis, Adrastea, and other unobserved parent bodies as the result of high-velocity impacts
The rings
must constantly be replenished with new dust from the moons to exist.
Actually, there are quite a bit about these rings that we are still in the dark about. And hopefully these would become clearer in the upcoming years.
Saturn’s hexagon is a hexagonal cloud pattern that has persisted at the North Pole of Saturn since its discovery in 1981. At the time, Cassini was only able to take infrared photographs of the phenomenon until it passed into sunlight in 2009, at which point amateur photographers managed to be able to photograph it from Earth.
The structure is roughly 20,000 miles (32,000 km) wide, which is larger than Earth; and thermal images show that it reaches roughly 60 miles (100 km) down into Saturn’s interior.
Read an explanation of how Saturn’s hexagon works here: [x]
Saturn’s fascinating geometry
From the images produced from Voyager and Cassini, scientists were able to develop models that commensurated with the data obtained. Here’s what they found :
The Hexagon is associated with an eastward zonal jet moving at more than 200 mph.
The cause of the Hexagon is believed to be a jet stream, similar to the
ones that we experience on Earth. The path of the jet itself appears to
follow the hexagon’s outline.
The Hexagon rotates at roughly the same rate as Saturn’s overall rotation.
While we observe individual storms and cloud patterns moving at
different speeds within the Hexagon, the vertices of the Hexagon move at
almost exactly the same rotational speed as that of Saturn itself.
How do we know this ?
We know this because we can experimentally reproduce the Saturn’s hexagon on earth in a laboratory. ( If you are interested in the technical details of the experiment – click here and here)
The setup is simple :
Researchers placed a 30-liter cylinder of water on a slowly spinning table. ( The water representing the Saturn’s atmosphere )
Inside this tank, they placed a small ring that spun more
rapidly than the cylinder. This created a miniature artificial “jet
stream” that the researchers tracked with a green dye.
These models however are still unable to dictate the exact phenomenon that is happening on Saturn, but surely they offer insight into the bizarre phenomenon that dwells in the celestial.
Bonus – Color Change
These images from the NASA’s Cassini spacecraft show the changing appearance of Saturn’s north polar region between 2012 and 2016.
The change is thought to be an effect of Saturn’s season ( Yes! Saturn has seasons ). Scientists are still probing into the causes for this change.
Sometime back, I was asked to explain the concept of pressure to
someone who had a tough time understanding it. And here is an account of
how that went:
The Books Analogy
Consider the layers of fluid stacked on top of each other to be represented by books instead of fluid.
Now, what does high pressure represent? Well, it just means that there are many books on stacked on top of each other. And what about the velocity?
Suppose
you apply a force and try to move this stack of books. Velocity is
nothing but how much this stack has moved in 1 second.
What does low pressure represent according to the books analogy? It
means that there are less books stacked on top of each other.
So, with
the same force you applied for the first case, you would be able to move
the books by a larger distance in one second. Hence it would have
higher velocity.
You can think of shock waves as these set of big books hurtled at supersonic speeds. And when they crash into objects, they break.
Subtle eh ?
The nuance of life is that we are constantly subjected to atmospheric pressure and yet we are oblivious to it.
Its profound because 1 Bar is considerable ( for instance, it can crush containers ). But yet here we are 🙂
Gravity and Atmospheric pressure
Standard Atmospheric Pressure is a product of gravity and the density and thickness of the gas in the atmosphere.
On
Earth, at sea level, the weight of a one square inch column of air from
the surface to the top of the atmosphere, (the tropopause, about 36,000
feet) is 14.7 pounds, or one bar, which is standard air pressure.
If
gravity had a higher value the atmospheric pressure would be
correspondingly higher because that column of air would weigh heavier.
Atmospheric
pressure on the top of Everest is much lower due to the considerably
shorter column of air above the summit, (plus the fact of slight
decrease in gravity, about 0.5%).
Atmospheric pressure on Venus is 33 bar or 33 times higher than on Earth. This is due to the higher gravity and the depth and density of the atmospheric gas.
Of all the planets in our solar system, Jupiter seems to stand out as this massive giants.
When scientists started uncovering the secrets of this mysterious planet, they discovered that Jupiter was probably a ‘star in the making’ during the early years of the solar system.
Jupiter and the sun
Jupiter has a lot in common with the sun than you think.
It is made of the same elements such as Hydrogen and Helium that are found in the sun and other stars!
But it is not massive enough and does not have have the pressure and temperature to fuse the existing Hydrogen atoms to form helium, which is the power source of stars.
How do stars form ?
Stars form directly from the collapse of dense clouds of
interstellar gas and dust. Because of rotation, these clouds form
flattened disks that surround the central, growing stars.
After the star
has nearly reached its final mass, by accreting gas from the disk, the
leftover matter in the disk is free to form planets.
How was Jupiter formed ?
Jupiter is generally believed to have formed in a two-step
process:
First, a vast swarm of ice and rock ‘planetesimals’ formed.
These comet-sized bodies collided and accumulated into ever-larger
planetary embryos.
Once an embryo became about as massive as ten Earths,
its self-gravity became strong enough to pull in gas directly from the
disk.
During this second step, the proto-Jupiter gained most of its
present mass (a total of 318 times the mass of the Earth).
But sadly soon
thereafter, the disk gas was removed by the intense early solar wind (from our sun) ,
before Jupiter could grow to a similar size.
This destroyed all hopes that Jupiter had on becoming a star
What if it had become a star ?
If Jupiter had become a star,our solar system would have
become a binary star system.
A binary star system is those systems having
two stars.they both revolve around themselves in their own orbits.
It is
interesting to note that most of the solar systems in the universe are
binary,triple or higher multiple star systems but our sun is rather
unusual.
In other star systems the mass distribution of the stars is equitable, but in ours the sun decided to not let that happen
Why? We have no clue ! Scientists are still trying to fathom these mysterious details of the birth process. But the more we know, the more we learn we don’t know 😀
We have seen a legion photographs of astronauts on the moon.
But how can we be sure that this was taken on the moon and not in some laboratory on earth? Well, because NASA says so !?
And How far is our moon?
Textbooks reluctantly write it as 384,400 km on average.But How on earth did they figure out how far the moon was? Can we quantify this value?
As a common man, is there any possible way to convince ourselves that we indeed
land on the moon and how far it is from earth – The answer is YES!. And this post is all about it.
What is a Retro reflector?
A Retro reflector is a device or surface that reflects light back to its source.
The most quotidian place to find one is on Bicycles, where it is installed for purposes of safety.
If you are the one with the cats, their eyes are coated with a fluid known as Tapetum Lucidum which mimics a retro reflector.
There are Retro reflectors placed on the moon
According to NASA, Retro reflectors were planted on the moon during the Apollo program (11, 14, and 15).
We are sure of this because if we aim lasers ( powerful ones ) on the moon, they are reflected back to the earth.
They can be identified as originating from the laser because the laser is highly monochromatic.
The distance to the Moon is calculated approximately using this equation:
Distance = (Speed of light × Time taken for light to reflect) / 2. (since distance=speed* time )
Can you test this in your backyard ?
Unfortunately no ! You would need highly sensitive detectors and a really powerful laser. But you can watch them in action at many places.
This is a requisite because the reflected light is too weak to be seen with the human eye:
Out
of 10^17 photons aimed at the reflector, only one will be received back
on Earth every few seconds, even under good conditions.
There you have it!
The distance between the moon and the earth measured and also conclusive proof that astronauts( or something else )did in fact land on the moon.
The Blue-Glowing Astronaut
This photo was taken during the Apollo-12 mission way back in 1969. But the reason for the blue glow is still not conclusive.
Orgonelab’s article – Astronaut Blues
takes you on a journey. A journey alongside with physicists and their
theories as they try to produce a rationale for this bizarre behavior.
It is highly recommended that you read it
Have a good day!
Photo Credit : NASA, Greg Hume, sciencedaily,Uniiversity of Winsconsin.
Mars has always been an interesting planet to us earthlings. The possibility of life, rovers leaving no stone unturned(literally), it’s demanding reddish appearance and now those breathtaking sunsets.Mesmerizing isn’t it ? But,
Why are martian sunsets blue?
Here on earth, sunsets are bright with Yellow, Orange and Red colors dazzling in the sky. During sunsets, the light from the sun has to travel a longer distance in our atmosphere to reach the earth.
Consequently, all the blue and violet light is scattered( thrown in various directions) by the particles in our atmosphere leaving behind only shades of yellow, orange and red, which is what you see. This phenomenon is known as Rayleigh scattering.
On mars, the reverse effect occurs. The martian dust is smaller and more abundant than on earth and it incidentally happens to be just the right size that it absorbs the blue light whilst scattering the red ones across the sky. This makes martian sunsets blue :).
Stay tuned, there is more space stuff coming your way.
Ecstasy Shots 