Elavenil

 Part 1- The birth of the universe

All the Epochs

-Gravity became the imposter and left the alliance. Only 3 of the 4 fundamental forces were unified.

  -Strong interaction

  -Weak interaction

  -Electromagnetism

-Gravity behaves according to the quantum mechanics and laws of physics may not 

- Inflationary, Quark, Hadron: Space becomes larger, by and order of 10^26, over a time of 10^-36 to 10^-32 seconds, cooling the universe by a lot. This resulted in the remaining 3 forces taking up the present forms. however, it was still too hot for the quarks to form hadrons. wWhen the temperatures dropped enough, quarks become hadrons and hadron Epoch started.

-Recombination Epoch

   -Electrons and Nuclei (protons and neutrons) form atoms

After the dark ages

-After the Dark ages: 

   -Universe becomes transparent, allowing light to travel long distances. However, there were very few light sources. The Universe contained only hydrogen gas and background radiation left over from the Big Bang. Over time, gravity piled the densest regions of hydrogen gas into compact clouds, which then collapased to form the first stars.

After the Dark Ages: 

The Stars: 

   -These stars were classified as Population III stars. 

   -Distinctively, they virtually had no metals. Extremerly massive, between few 100 to 1000 solar masses. Extremely luminous.

The birth of stars accelerated as the Universe left the dark ages

-Galaxy mergers

  -Gravity eventually caused galaxies to merge together.

-The birth of planets

  -The Sun and the planets formed together,4.6 billion years ago, from a cloud of gas and dust called asolar nebula

-The birth of moons

  -The moon likely formed after a Mars-sized body, Theo, collided with Earth several billion years ago.

  -The resulting debris from both Earth and the impactor accumulated to form our natural satellite, the Moon.

-The first blackholes

  -Stellar black holes--Formed from the collapse of stars, can be formed if neutron star absorb enough material from nearby binary star or object causing neutron star to collapse.

  -can also be formed directly due to a large enough star undergoing Type II supernova                                                    - black holes can be formed as long as cores/remains of collapsed stars are greater than 5 solar masses, causing an escape velocity greater than speed of light. Stars must be greater than 20 masses for the above stated condition to occur.

  -Supermassive black holes: Theories

     -clouds of gas in early universe have variation in density and those that are super dense created black holes immediately

     -large stars formed during the early stage of the universe created super black holes when they died 

     -rapid formation of galaxies in the early stage of the universe fuelled black holes to grow larger

Part 2- The beginning of the end

-Nuclear fusion: It is the process when 2 different molecules collide with each other with intense forces to the point when they fuse together, releasing massive amounts of energy.

Intermediate Mass Stars are heavier but not heavy enough for massive explosions. They are capable of fusing helium into heavier elements such as carbon and oxygen, shortening their life span. They also would collapse into a white dwarf. However, it can take trillions of years.

-White Dwarfs: They are the remains of Intermediate Mass Stars. They are incredibly dense and have a mass of about the Sun's while having a volume of about the Earth's. When it collapses on itself, all the remaining mass is compressed into the star's core, thus making it dense and heavy.

-High mass stars- These insane stars are the biggest in our universe, at around 7 to 10 times heavier than our Sun.

Supernovas

-The cores of Type II supernovas are usually obliterated or turned into other things during this process. Hence, white dwarfs are very uncommon to appear.

-Type Ia supernova involves one white dwarf orbiting another star.

-The other star could be a white dwarf or a bigger star.

-Usually, the white dwarf accumulates matter from the other star until a reaction is known as a "Runaway Nuclear Reaction" ignites.

-This leads to the white dwarf explodes.

Neutron stars

-This is one of the things a star becomes after exploding.

-Pulsars are the most common form of neutron stars.

-They emit pulses of strong energy at intervals while also having powerful magnetic fields which shoot out particles from each pole.

-Another type of neutron star is a magnetar. In a typical neutron star, the magnetic field is trillions of times that of the Earth's magnetic field. However, the magnetic field is another 1000 times st.

Blackholes 

-When the star collapses, an imaginary surface called the 'event horizon' forms; this is the point where light cannot even escape the black hole.

-According to Einstein's Theory of Relativity, under the influence of strong gravitational forces, time starts to slow down.

Part 3- The End

The death of white dwarfs, The death of black holes

Degenerate Era: As Stars explode like fireworks in the sky, the planets that reside near their stars will get vaporised. The temperature decreases as all material from a companion. A black hole "survive" by star white dwarf preaching objects into its event horizon. In the end, the black hole lights up the universe for the last time. 

The death of protons

-Proton decay

-A hypothetical form of particle decay in which the proton decays into lighter subatomic particles such as protons and pions

The Death of the Universe: 

-When the universe's expansion eventually reverses and the universe re-collapses, it ultimately causes the cosmic scale factor to be zero. When all the heat and energy are evenly spread, then, the United across the universe, this will happenverse, atom, subatomic particles and even spacetime itself is progressively torn apart by the expansion of the Universe.

THE END.

Extra-Terrestrial Life

Fermi-Paradox and its many wonders

CONTENTS:

-Habitability

-Fermi-Paradox

-Dark Forest Theory

-Seager Equation

Habitability

• In all known forms of life, water and sufficient amounts of certain air qualities are the basis for their existence.

• Some important elements include Carbon, Hydrogen, Oxygen and Nitrogen

• The habitable zone, AKA the Goldilocks Zone, is a region where planets can be at a sufficient temperature that is not too warm or cold

• This allows us to gauge possible worlds that contain life

Fermi-Paradox

• It is an apparent contradiction for the lack of evidence and high probability estimates for the existence of extra-terrestrial life.

• There is an 'evolutionary path' that intelligent life would have to take before discovering other colonies of extra-terrestrial origin or us

• The absence of any sign of intelligent life in space would mean that one of the steps is improbable to work

• If one step fails, the intelligent life would start from scratch

The Dark Forest Theory

It's to be the hunter or be the hunted

• To find possible extra-terrestrial life, radio signals are used

• Search for Extra-Terrestrial Life is scientific searches using electromagnetic radio waves

• If alien life were to be advanced enough, we would find megastructures, acting as a sort of lighthouse

Seager Equation

• This is a reworking of the Drake equation

N = N*FQFHZFOFLFS

N = the number of planets with detectable signs of life

N* = the number of stars observed

FQ = the fraction of stars that are quiet

FHZ = the fraction of stars with rocky planets in the habitable zone

FO = the fraction of those planets that can be observed

FL = the fraction that has life

FS = the fraction on which life produces a detectable signature gas

Black Holes

Introduction to black holes

• A black hole is a place in space where gravity pulls so much that even light cannot get out.

• We cannot see black holes as their strong gravity pulls all the surrounding light into the center of the black hole. Black holes are observed by their effect on the surroundings. The black hole in the center of the Milky Way is called Sagittarius A*.

• The smallest black holes can be as small as one atom yet have a mass of a small mountain

• The largest black holes can be as big as a few million Earths combined and can have the mass equal to around 4 million suns. These black holes are called supermassive black holes.

      What types of black holes are there?

• The 4 types of black holes are stellar-mass, intermediate, supermassive and miniature. Stellar-mass are the most common black holes, ranging from 5 to 10 times the mass of the sun.

• Intermediate: significantly more massive than a stellar black hole. However it has less mass. The intermediate black holes can range from 100 to a million times more massive than the sun.

• Supermassive: largest type of black holes, ranging from millions to billions of times the mass of our sun.

• Miniature: hypothetical tiny black holes. The size of these black holes may be equal to or above 22.1 micrograms, which is about one millionth of a gram.

      How are black holes created?

• Stellar-mass: when the center of a very big star collapses. When this happens, it causes a supernova. A supernova is an exploding that blasts part of the star into space.

• Intermediate:  it is too massive to be formed by the collapse of a single star. One theory is as to how intermediate black holes are formed is that stellar black holes gravitationally attract other stellar black holes or compact objects. The merging of these black holes and compact objects forms intermediate black holes.

• Supermassive: unconfirmed. Some have suggested that supermassive black holes form out of the collapse of massive clouds of gas during the early stages of the formation of the galaxy.

• Miniature: a black hole created soon after the creation of the universe is called a primordial black hole and is the most widely accepted hypothesis for the possible creation of micro black hole.

How to photograph black holes

• Event Horizon Telescope: capture an image of a black hole

• Very Long Baseline Interferometry: creating an array of smaller telescopes that can be synchronised to focus on the same object at the same time and act as a giant virtual telescope

    Parts of a black hole

• There are 6 main parts of a black hole. There are, however, 2 more aspects not being mentioned.

• Event horizon: ''point of no return''. Once matter is inside it, that matter will fall to the center. With such strong gravity, the matter squishes to just a point- a tiny, tiny volume with a big density.

• Singularity: that is the point. It is vanishingly small, so it has essentially an infinite density which makes it likely that the laws of physics break down at the singularity. It is found at the centre of a black hole and it exerts a strong gravitational force for any object that falls in. This process is known as spaghettification.

    Theories

• White holes: the polar opposites to black holes. Also contain a singularity, but they operate in reverse to a black hole. Nothing can enter the event horizon of a white hole and any matter inside the white hole gets ejected immediately.

• Wormholes: because the white and black hole would exist in separate places in space, a tunnel- a wormhole - would bridge the two ends. A wormhole describes Einstein's theory of general relativity that connects two distant points in space or time via a tunnel.

• However, wormholes would not be very useful. They are super unstable. If a particle dropped towards the event horizon of a white hole, it would never reach since nothing can enter a white hole. Hence the energy of the system increases to infinity and the white hole explodes.

• The entrance of a (hypothetical) wormhole would be a sphere. I f you looked into it, you would see light coming in from the other side. The tunnel could be any length, and while travelling down the tunnel you would see distorted views of the region of the universe you came from and the region you were travelling to.

• A wormhole could also act as a time machine. Special relativity dictates that moving clocks run slowly. In other words, initially the two ends will be synchronised in time, but if one end was then accelerated to the speed of light, that end would lag behind the other end. The two entrances could then be brought together but one of the entrances would be in the past of the other.

Hawking radiation

• Quantum fluctuations- the temporary random change in the amount of energy in a point in space

• Annihilation- the conversion of matter into energy, especially the mutual conversion of a particle and an antiparticle into electromagnetic radiation

• Eon- a period in time equal to a thousand million years

• Hawking radiation is the thermal radiation predicted to be spontaneously emitted by black holes. It arises from the steady conversion of quantum vacuum fluctuations into pairs of particles, one of which is escaping at infinity while the other is trapped inside the black hole horizon.

     Exoplanets

     What are exoplanets?

• Exoplanets refer to planets outside our solar system.

• They orbit around their own stars, forming their own solar systems.

• Most orbit other stars, but there are free-floating exoplanets, called rogue planets, orbit the galactic center and are untethered to any star.

Examples of exoplanets

• Goldilock's Zone is the habitable zone, which is the area around the star where it is not too hot and not too cold for liquid water to exist on the surface of surrounding planets. In other words, the temperature of the habitable zone is just right for liquid water to exist.

• Kepler-186f was the first rocky planet to be found within the Goldilock's zone. It is similar in size to Earth

• 'Osiris' was the first planet to be seen in ''transit''.

• 51 Pegasis b is about half the mass of jupiter and orbits its star every 4 days.

• Kepler- 444 system is the oldest known planetary system and has 5 terrestrial-sized planets, all in orbital resonance.

• Kepler-22b is a possible water-world planet unlike any seen in our solar system

     History of Exoplanets

• The first exoplanet:

-After much of Carl Sagan's theory, in 1992, astronomers discovered the first exoplanet. But it didn't come in any form they expected. It was found through emitting pulsars.

How to detect exoplanets

• Dopper spectroscopy

-Centre of gravity in space

- Two or more objects orbiting around each other have a center of mass

- as the exoplanets orbit around a star, the barycentre of a sun is important

- if a star has planets, the star orbits around a barycentre

- since the mass of a star is mostly significantly larger than that of the planet, the center of mass of the system usually lies within the star

Transits:

- transit-timing variation is a method for detecting exoplanets by observing variations in the timing of a transit.

- this provides an extremely sensitive method capable of detecting additional planets in the system with masses potentially as small as that of Earth

Pulsar timing:

• pulsars are rotating neutron stars observed to have pulses of radiation at very regular intervals that typically range from milliseconds to seconds

• by tracking the motion of pulsars, the orbit parameters can be determined and exoplanets can be detected.

          Direct imaging:

• Imagine taking a picture with a camera that can include frequencies of light beyond visible spectrum

• 
  

         Gravitational microlensing:

- this technique is premised in general relativity, where the light from a star can be bent by the gravity

- however this technique relies on a chance alignment between the source star, the lens star, and the observer, and that is not common

          Astrometry:

• involves measuring a star's position in the sky accurately, and detecting how that position changes over time.

• since a star with a planet will orbit around the common barycentre of the the system, the star's position in the sky can be used to detect signs of this orbit.

SPACEFLIGHT SIMULATOR

ROVERS

WHAT are ROVERS for?

They are exploration devices designed to traverse extraterrestrial surfaces.

Rovers can have multiple uses:

• Transporting human spaceflight crew

• Partial/fully autonomous robot

• Rovers collect data about terrain and collect crust samples such as dust, soil, rocks, and even liquids. They are essential tools in space exploration.

• Rovers can have many objectives, but their main ones are:

• - Determine the geological processes that shaped the terrain of the region

• -Study the composition of rock and soil to find evidence of water

• - Study the environmental conditions that existed when liquid water was present and access whether life could develop there.

HOW are ROVERS designed. (Landing)

Rovers are lander spacecrafts. They have soft landings that keep the machinery functioning. 

They have multiple ways of achieving this:

• Employing parachutes to have low terminal velocity

• Firing small rockets before impact

• Using sensors to ensure a controlled descent

• Deploying airbags to cushion impact

KSP LESSON TWO

Depending on the rockets’ TWR the time where we start to do the gravity turn changes. A gravity turn is decreasing the pitch of the rocket to more efficiently get into orbit. 

Parachutes - works well as long as the payload is small and if there is an atmosphere

Burning back - works well in all conditions as long as there is fuel and u know what you are doing

How to land?

Just fire your rocket engine retrograde and make sure your speed relative to ground on touchdown < 7m/s or else your rocket have a rapid unscheduled disassembly 

SATELLITES

Space station and crafts

• support human crew for extended period of time

• this is for scientific purposes such as to study the effects of spaceflight on the human body and other organisms, as well as to provide a location to conduct a greater number and longer length of scientific studies in space

• communication:

                             - antennas are used to send and receive signals continuously

• Disposal: satellites outside earth- de-orbiting, which is similar to graveyard orbit, and controlled entry, which is launching the satellite to the atmosphere of the planet for them to burn up, like in LEO for earth satellites

MORE KSP 11/5/22

Rovers in KSP are EVs (electric vehicles), small, complex, and very useful

CONSTELLATIONS