Heaven and Earth

Heaven and EarthRiz Rahman

Earth, sun and solar system

Earth, sun and solar systemFormed 4.6 billions years ago.

Sun and all planets were born together from the collapse of a giant molecular cloud.

Vast majority of the system's mass is in the Sun, with most of the remaining mass contained in Jupiter.

Earth, sun and solar systemMercury, Venus, Earth and Mars - four smaller inner terrestrial planets - primarily composed of rock and metal.

Then, we have the asteroid belt.

Jupiter, Saturn, Uranus, Neptune - four outer planets, or the gas giants

Jupiter and Saturn - composed mainly of hydrogen and helium.

Uranus and Neptune - composed of iced gases - water, ammonia and methane

All planets have almost circular orbits that lie within a nearly flat disc called the ecliptic plane.

Beyond NeptuneBeyond Neptune's orbit lie the Kuiper belt and scattered disc - trans-Neptunian objects composed mostly of ices.

Beyond NeptuneSeveral dozen to more than 10,000 objects may be large enough to have been rounded by their own gravity - dwarf planets.

Asteroid Ceres and the trans-Neptunian objects Pluto, Eris, Haumea, and Makemake.

Comets, centaurs and interplanetary dust freely travel between regions.

Oort cloud Hypothesized spherical cloud of comets - nearly a light-year, from the Sun.

A quarter of the distance to Proxima Centauri, the nearest star to the Sun

Oort cloudThe outer limit of the Oort cloud defines the cosmographical boundary of the Solar System and the region of the Sun's gravitational dominance.

Sedna is a large trans-Neptunian object, which is about three times as far from the Sun as Neptune.

Solar system completedThe Solar System is located within one of the outer arms of Milky Way galaxy, which contains about 200 - 400 billion stars.

Wait Lets compare Sun

Nearest starsProxima Centauri - a red dwarf star about 4.24 light-years distant from Sun.

Too faint to be seen with the naked eye.

Second- and third-nearest stars - the bright binary Alpha Centauri

Proxima Centauri may be part of a triple star system with Alpha Centauri A and B.

Nearest stars

Milky WayThe Milky Way is the galaxy that contains our Solar System.

Milky Way

Milky Way - FactsA spiral galaxy 100,000120,000 light-years in diameter

Containing 200400 billion stars - may contain at least as many planets.

Center is marked by an intense radio source named Sagittarius A* which is likely to be a supermassive black hole.

Rotates differentially, faster towards the center and slower towards the outer edge.

The rotational period is about 200 million years at the position of the Sun.

The Galaxy as a whole is moving at a velocity of 552 to 630 km per second.

It is estimated to be about 13.2 billion years old, nearly as old as the Universe.

Surrounded by several smaller satellite galaxies, the Milky Way is part of the Local Group of galaxies, which forms a subcomponent of the Virgo Supercluster.

Virgo SuperclusterContains the Virgo Cluster in addition to the Local Group, which in turn contains the Milky Way and Andromeda galaxies.

At least 100 galaxy groups and clusters are located within its diameter of 33 megaparsecs (110 million light-years).

It is one of millions of superclusters in the observable Universe.

Nearest GalaxyAndromeda Galaxy

AndromedaApproximately 2.5 million light-years from Earth.

Contains one trillion (1012) stars: at least twice the number of stars in the Milky Way.

Visible at naked eye.

The two galaxies are expected to collide in 3.75 billion years, eventually merging to form a giant elliptical galaxy.

There are probably more than 170 billion (1.7 1011) galaxies in the observable Universe.

Furthest galaxiesMACS0647-JD - a candidate for the farthest known galaxy from Earth and is at 13.3 billion light-years away.

It formed 420 million years after the Big Bang. It is less than 600 light-years wide.

Quasars, pulsars and neutron starsPulsar - is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. Acts as a light house.

Quasars, pulsars and neutron starsNeutron stars - is a type of stellar remnant that can result from the gravitational collapse of a massive star.

Composed almost entirely of neutrons.

Very dense - A typical neutron star has a mass between about 1.4 and 3.2 solar masses with a corresponding radius of about 12 km - approximately equivalent to the mass of a Boeing 747 compressed to the size of a small grain of sand.

Some neutron stars rotate very rapidly and emit beams of electromagnetic radiation as pulsars.

Quasars, pulsars and neutron starsQuasar - is a very energetic and distant active galactic nucleus.

The most luminous, powerful, and energetic objects known in the universe.

A compact region in the center of a massive galaxy surrounding its central supermassive black hole.

Quasars

QuasarsThey tend to inhabit the very centers of active young galaxies and can emit up to a thousand times the energy output of the Milky Way.

When combined with Hubble's law, the implication of the redshift is that the quasars are very distantand thus, it follows, objects from much earlier in the universe's history.

Universe

UniverseCommonly defined as the totality of existence, including planets, stars, galaxies, the contents of intergalactic space, and all matter and energy.

At least 93 billion light years in diameter.

Has been governed by the same physical laws and constants throughout most of its extent and history.

Big Bang Theory - about 13.7 billion years ago.

Big Bang Theory

Big Bang Theory

Observable UniverseSome parts of the universe may simply be too far away for the light emitted from there at any moment since the Big Bang to have had enough time to reach Earth at present, so these portions of the universe would currently lie outside the observable universe.

In the future the light from distant galaxies will have had more time to travel, so some regions not currently observable will become observable in the future.

Dark matter and dark energyDark matter

hypothesized to account for a large part of the total mass in the universe.

cannot be seen directly with telescopes; evidently it neither emits nor absorbs light or other electromagnetic radiation.

inferred from its gravitational effects on visible matter, radiation, and the large scale structure of the universe.

Dark matter and dark energyDark energy

hypothetical form of energy that permeates all of space and tends to accelerate the expansion of the universe.

is the most accepted hypothesis to explain that the universe is expanding at an accelerating rate.

Dark matter and dark energy

Theories about the end of the universeBig Freeze or heat deathBig RipBig Crunch - This scenario allows the Big Bang to be immediately after the Big Crunch of a preceding universe - cyclic model of oscillatory universe.Big BounceFalse vacuumCosmic uncertaintyMultiverse

Multiversethe hypothetical set of multiple possible universes (including the historical universe we consistently experience) that together comprise everything that exists and can exist: the entirety of space, time, matter, and energy as well as the physical laws and constants that describe them. The various universes within the multiverse are sometimes called parallel universes.

Fermi ParadoxThe Sun is a young star. There are billions of stars in the galaxy that are billions of years older;

Some of these stars likely have Earth-like planets which, if the Earth is typical, may develop intelligent life;

Presumably some of these civilizations will develop interstellar travel, as Earth seems likely to do;

At any practical pace of interstellar travel, the galaxy can be completely colonized in just a few tens of millions of years.

Where is everybody?

Thank you