A brief look out at the space we know today

Updated: May 15


Image Credit: Unsplash
Image Credit: Unsplash

When we look at a cloudless night in the sky we can see thousands of stars in the sky. From the human perspective view that is known as space (The outer space is a zone that occurs about 100 kilometers (60 miles) above the planet Earth). The namespace is given by humans due to the massive empty areas in between the atmospheres of stars and planets, apart from the odd rocks, space is sprinkled only with dust and gas. We call space is a universe because exoplanets, Solar systems, Stars, Planets, Earth, galaxies, sun, dust, gas, rock, and other things stay inside the universe. Space knew a 3D region where the atmosphere of Earth ends. We can maintain satellites in the low orbit at a particular time without falling into the atmosphere. It is believed that this low orbit space is beginning.


When we think about space, the first thing that comes into our mind that
  • Space is weightless because everything floats due to no gravity

  • Space is nothingness because the vast areas of space are completely empty

  • Space contains stars a burning ball of gas and planets, dust, rocks, comets, and many more...

  • Astronauts go the space travel and they explore the space beyond our Earth

  • Rockets and Satellites deployed in space are man-made artificial machines. This thing helps scientists to explore the space world

  • Space is too much silence, even a sound cannot pass because space is like a vacuum and there is no air in space to breathe

  • There is no scatter light in space

  • Space is big. No one knows how much it is bigger or smaller.

  • We can see small portions of space through our telescopes from Earth and deployed telescopes in space.

  • Space is measured in light-years. The formula of light is 3 X 10^8 to calculate the light year.

  • Space is too dark and it feels scary.

  • Outer space is a hard vacuum containing a low density of particles, predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, neutrinos, dust, and cosmic rays

The sound cannot carry in space because the molecules in space are not enough to transmit sound between them. In our empty space gas, dust and other matters are floating. The most important thing in the crowded area cannot host stars, planets, and galaxies. Light travel in space is expected around 9.3 Trillion kilometers in a light year.


The beginning of space is believed that happens through a big bang 13.7 billion years ago. Astronomers have no guarantee that how many universes exist. Some believe a multiverse exists, some in a single universe, and some belief in an infinite universe. Nowadays astronomers believe in a parallel universe, a parallel timeline. These timelines same as our world may exist in the multiverse.


Intergalactic space takes up most of the volume of the universe but even galaxies and star systems consist almost entirely of empty space.


Space holds many secrets and it contains places where people at large are often stretched into spaghetti shapes or boiled or frozen solid. Astronauts wear protective clothing in space and it helps from these kinds of ridiculous things. Humans designed the spacecraft to work in a zone with no atmosphere and there was no need for smooth edges or an aerodynamic shape.


Some space term is
  • interplanetary space (space between planets in our solar system)

  • interstellar space (space between stars in our galaxy)

  • intergalactic space (space between galaxies in the universe)

Space has no friction for allowing stars, planets, and moons to move freely along their ideal orbits following the initial formation stage. The deep vacuum of intergalactic space is not devoid of matter because it contains a few hydrogen atoms per cubic meter The low density of matter in space means that electromagnetic radiation can travel great distances without being scattered. The mean free path of a photon in intergalactic space is about 1023 km or 10 billion light-years. In spite of this extinction, which is the absorption and scattering of photons by dust and gas is an important factor in galactic and intergalactic astronomy.

Stars, planets, and moons retain their atmospheres by gravitational attraction. Atmospheres have no clearly delineated upper boundary. The density of atmospheric gas gradually decreases with distance from the object until it becomes indistinguishable from space. Magnetic fields have been detected in space around every class of celestial object. Star formation in spiral galaxies can generate small-scale dynamos creating turbulent magnetic field strengths of around 5–10 μG.


The Davis–Greenstein effect causes elongated dust grains to align themselves with a galaxy's magnetic field, resulting in weak optical polarization. This has been used to show that ordered magnetic fields exist in several nearby galaxies. Magneto-hydrodynamic processes in active elliptical galaxies produce their characteristic jets and radio lobes. Non-thermal radio sources have been detected even among the most distant, high-z sources, indicating the presence of magnetic fields.


Galaxies contain billions of stars. Our galaxy, Milky Way is a barred spiral galaxy. There are different types of galaxies in space in different shapes and some astronomers are able to find them very easily. These galaxies contain supermassive black holes, planets, stars in different colors...etc. These black holes are only visible through the radiation that each black hole emanates as well as through its gravitational interactions with other objects. If the black hole is particularly active with a lot of material falling into it, it produces immense amounts of radiation. This kind of galactic object is called a quasar. Large groups of galaxies can form clusters that group as large as hundreds or thousands of galaxies bound together gravitationally. Scientists consider these the largest structures in the universe.

Radiation in space


There are different kinds of radiation that exist in our universe. Cosmic rays also fly through the neighborhood emanating from supernovas outside of the solar system. The universe is permeated by the cosmic microwave background, which can be understood as the leftovers of the immense explosion that formed our cosmos (usually called the Big Bang). The cosmic microwave background which is best seen in microwaves shows the earliest radiation that our instruments can detect.


All of the observable universes are filled with photons that were created during the Big Bang known as the cosmic microwave background radiation (CMB). There is quite likely a correspondingly large number of neutrinos called the cosmic neutrino background.


Stars like our sun can produce radiation. When stars become out of fuel, that star explodes as supernovae happen, after then radiations also come out from supernovae. They can range from red supergiants stars to cooling white dwarfs stars that are the leftovers of supernovas. These explosions can give neutron stars. When these neutron stars send out pulses of radiation are called pulsar stars.


Temperature: 2.7 kelvins (−270.45 °C; −454.81 °F)


The baseline temperature of outer space is set by the background radiation from the Big Bang. The temperature of space is measured by the kinetic activity of the gas. The radiation of space has a different temperature than the kinetic temperature of the gas, meaning that the gas and radiation are not in thermodynamic equilibrium. The gas temperatures in space can vary widely, for example, the temperature in the Boomerang Nebula is 1 K while the solar corona reaches temperatures over 1.2–2.6 million K

Why is space so dark?


Space is black because there's nothing there to reflect light and if you look up Earth from space it looks lit up because light from our Sun reflects off sea, land, and the particles of our Earth's atmosphere. The scattered light from the Sun in that Earth's surface area blue gives way to black because oxygen molecules are not enough abundance to make the sky blue.


There are different kinds of a mix of gases that help to produce up our atmosphere and it doesn't simply finish suddenly because it fades step by step when we go above the Earth into space we can see that. Earth is cloaked in a layer of gases, it is called the atmosphere. You want to know that the outside atmosphere is space and there is no air to breathe or to allow wings to fly. There is nobody can hear your scream also.


Different layers of gases in the Earth's atmosphere

  • Troposphere:- Between 6 to 20 km (3 ½ to 12 miles) above the ground and all the weather takes place here.

  • Stratosphere:- This layer stays 50 km (31 miles) above the Earth and the Planes cruise in the upper troposphere or lower stratosphere above the clouds.

  • Mesosphere:- This layer stays 85 km (53 miles) above the ground and the air becomes thin. This thin air is still thick enough to slow meteorites down and most of the experts agree that space begins at 100 km (63 miles) above the ground level from Earth. This line is known as the Kármán line (100 km (63 miles) above the ground level from Earth)

  • Thermosphere:- It reaches far to 700 kilometers (over four hundred miles) higher than Earth and the polar lights (aurora borealis in the north and aurora in the south) happen in the thermosphere.

  • Exosphere:- It is the outer layer of the atmosphere and extends 10,000 km (6,000 miles) higher than the bottom ground. The lighter gases drift into space on the far side of the exosphere.

The Earth's atmospheric pressure drops to about 0.032 Pa at 100 kilometers (62 miles) of altitude compared to 100,000 Pa for the International Union of Pure and Applied Chemistry (IUPAC). Above this altitude, isotropic gas pressure rapidly becomes insignificant when compared to radiation pressure from the Sun and the dynamic pressure of the solar wind. The thermosphere in this range has large gradients of pressure, temperature, and composition, and varies greatly due to space weather.


Outside a protective atmosphere and magnetic field in Earth and there are few obstacles to the passage through space of energetic subatomic particles known as cosmic rays. These particles have energies ranging from about 106 eV up to an extreme 1020 eV of ultra-high energy cosmic rays. The peak flux of cosmic rays occurs at energies of about 109 eV with approximately 87% protons, 12% helium nuclei, and 1% heavier nuclei. In the high energy range, the flux of electrons is only about 1% of that of protons. Cosmic rays can damage electronic components and pose a health threat to space travelers.


According to astronauts Don Pettit, space has a burned/metallic odor that clings to their suits and equipment similar to the scent of an arc welding torch.


Do you know where our space begins?


Till now none of no humans can find where our space begins. Some astronomers believed that 13.7 billion years ago space begins from the big bang and we can see that much of the distance of space only.


There is no proper estimated boundary between Earth and the atmosphere. When traveling to space the density of the atmosphere decreases.

  • Fédération Aéronautique Internationale:- Established the Kármán line at an altitude of 100 km (62 mi) as a working definition for the boundary between aeronautics and astronautics.

  • The United States designates people who travel above an altitude of 50 mi (80 km) as astronauts.

  • NASA's Space Shuttle used 400,000 feet (122 km, 76 mi) as its re-entry altitude (termed the Entry Interface) which roughly marks the boundary where atmospheric drag becomes noticeable. Thus begins the process of switching from steering with thrusters to maneuvering with aerodynamic control surfaces.

Other features of Space


The presence of dark matter and dark energy are essentially forms of matter and energy that can only be detected through their effects on other objects. The expert believes that the universe is expanding and accelerating in that expansion and it can be seen as one key piece of evidence for dark matter. 90% of the mass in most galaxies is in an unknown form called dark matter and it interacts with other matter through gravitational but not electromagnetic forces. The majority of the mass-energy in the observable universe is dark energy and it is a type of vacuum energy known as dark matter that is poorly understood till now by experts.


Another is gravitational lensing which occurs when light bends around a star from a distant background object.


Black Holes


Another important thing in space is the Black Hole. Nothing can escape from a black hole including light. There is no one has any idea what's happening inside the black hole and what will happen when a living being entered I black hole. There are thousands of researches are ongoing regarding the Black Hole and the results like unexpected mysteries. Albert Einstein first predicted the existence of black holes in 1916 with the help of gravitational waves.


Black Holes evolved from the gravitational collapse of stars. Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration announced in 2017 that three black hole interactions and mergers were detected through gravitational waves. These three events occurred in about two years indicating that when LIGO is implemented at full sensitivity.

Do you know?

  • A nebula could be a cloud of dust and gas in space.

  • If you'll drive a car straight up, it might take only about an hour to arrive in space.

  • You want to know that astronomers measure distance in space is called a light-year. Do you know that one light-year is the distance light travels in one year i.e. 10 million kilometers (6 million miles)? Astronomers measure space distances in light years because the distances are so great that normal measurements have little meaning. You can say, a light-year is the distance light travels in a year.

  • When we drive an automobile straight up above the sky and it takes only an hour to reach space.

  • International space law was established by the Outer Space Treaty and it entered into force on 10 October 1967. This treaty precludes any claims of national sovereignty and permits all states to freely explore outer space. The drafting of UN resolutions for the peaceful uses of outer space anti-satellite weapons has been tested in Earth orbit.

  • 2009:- Scientists reported detailed measurements with a Supra Thermal Ion Imager (an instrument that measures the direction and speed of ions) which allowed them to establish a boundary at 118 km (73.3 mi) above Earth. The boundary represents the midpoint of a gradual transition over tens of kilometers from the relatively gentle winds of the Earth's atmosphere to the more violent flows of charged particles in space, which can reach speeds well over 268 m/s (600 mph).

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