After having celebrated the Fourth of July with family gatherings and fireworks, let us take a moment to look up at the sky and understand and admire the celestial “fireworks” that have been raging for billions of years and will continue for billions more, forging atoms, molecules, stars, galaxies, black holes, planets and life, while putting on quite a dazzling show for those who can observe.
Feel free to let out a few Oohs and Aahs ;)
Nebula NGC 3603
NGC 3603 is a nebula situated in the Carina spiral arm of the Milky Way around 20,000 light-years away from the Solar System contains a young, glittering collection of stars resembling a July 4 fireworks display.
Ultraviolet radiation and violent stellar winds have blown out an enormous cavity in the gas and dust enveloping the cluster. Most of the stars in the cluster were born around the same time but differ in size, mass, temperature and color. The course of a star's life is determined by its mass, so a cluster of a given age will contain stars in various stages of their lives. NGC 3603 also contains some of the most massive stars known. These huge stars live fast and die young, burning through their hydrogen fuel quickly and ultimately ending their lives in supernova explosions.
SuperNova and The Crab Nebula
The Crab Nebula, the result of a bright supernova explosion is 6,500 light-years from Earth. The explosion was observed by Chinese and other astronomers on July 4, 1054 when it was bright enough to be seen in the daytime! At its center is a super-dense neutron star, rotating 30 times a second, shooting out rotating beams of radio waves and light — a pulsar (the bright dot at image center). The nebula's intricate shape is caused by a complex interplay of the pulsar, a fast-moving wind of particles coming from the pulsar, and material originally ejected by the supernova explosion and by the star itself before the explosion.
A Lonely Neutron Star
Neutron stars are the ultra dense cores of massive stars that collapse and undergo a supernova explosion. Astronomers have discovered a rare kind of neutron star outside the Milky Way, that has both a low magnetic field and no stellar companion.
The neutron star is located within the remains of a supernova — known as E0102 — in the Small Magellanic Cloud, located 200,000 light years from Earth.
Star Formation also cause Stellar Explosions
An explosion in the Orion Molecular Cloud 1 (OMC-1) 1350 light years away, in the constellation of Orion (the Hunter), 500 years ago, caused this firework-like debris from the birth of a group of massive stars, demonstrating that star formation can be a violent and explosive process too.
Galactic Mergers
An international team of astronomers has estimated that 8 to 10 billion years ago, a dwarf galaxy dubbed the “Sausage” galaxy smashed into our Milky Way galaxy. The merger reshaped the structure of our galaxy, fashioning both its inner bulge and its outer halo.
Galaxies collide, merge and pass through each other over large time scales, driven by their gravitational forces. The rose-like twin galaxy Arp 273, 300 million light years away in the constellation Andromeda, was formed as the smaller galaxy passed through the larger one.
Stellar Winds and Cosmic Rays
A new study using data from NASA’s NuSTAR space telescope suggests that Eta Carinae, the most luminous and massive stellar system within 10,000 light-years, is accelerating particles to high energies — some of which may reach Earth as cosmic rays.
Eta Carinae, located about 7,500 light-years away in the southern constellation of Carina, contains a pair of massive stars whose eccentric orbits bring them unusually close every 5.5 years. The stars contain 90 and 30 times the mass of our Sun and have a combined luminosity greater than five million times that of the Sun. Both stars drive powerful outflows called stellar winds, which emit low-energy X-rays where they collide.
Eta Carinae is famous for a 19th century outburst that briefly made it the second-brightest star in the sky between 11 and 14 March 1843. www.nasa.gov/...
Black Holes produce a lot of fireworks
Black holes are “black” since even light cannot escape them. But black holes cause a lot of mayhem around them, spaghettifying and devouring stars around them and releasing astronomical amounts of energy in the process.
Gamma-Ray Bursts
Gamma-ray bursts are the most luminous explosions in the cosmos. Most of these events occur when the core of a massive star runs out of nuclear fuel, collapses under its own weight, and forms a black hole. The black hole then drives jets of particles that drill all the way through the collapsing star at nearly the speed the light.
On April 27, 2013, a blast of light from a dying star in a distant galaxy 3.6 billion light-years away reached earth. The explosion designated GRB 130427A, topped the charts as one of the brightest ever seen. The Fermi Large Area Telescope detected gamma-rays from this event for a record-setting 20 hours.
The Gamma-ray Bubble
What a sight this must be to behold by inhabitants of a nearby galaxy! Two giant bubbles emitting gamma-rays, on either side of the Milky way plane. These bubbles of high-energy radiation are suspected as erupting from a massive black hole or evidence of a burst of star formations from millions of years ago.
My God, it’s full of Stars and Galaxies!
The observable Universe is estimated to have over two trillion galaxies and about 1024 stars. A star explodes into a supernova every second or so somewhere in the universe.
Close to our Solar System
Our sun is ablaze with light and energy that drive weather, biology and more on Earth. The sun also sends out a constant flow of particles called the solar wind, and it occasionally erupts with giant clouds of solar material, called coronal mass ejections, or explosions of X-rays called solar flares.
Close to Earth
Terrestrial Gamma-ray Flashes (TGFs) are formed above intense thunderstorms. TGFs produce a beam of high-speed electrons and positrons (antimatter counterpart of the electron), which then ride up Earth's magnetic field. Collisions between positrons and normal electrons result in annihilation and production of high energy gamma rays that can be detected by space based detectors such as Fermi. The Atmosphere-Space Interactions Monitor (ASIM), an experiment dedicated to study TGFs, was launched to the International Space Station on 2 April 2018.
Here at home -
Our Future
Hubble observations indicate that our Milky Way galaxy will collide with the nearby Andromeda galaxy, in about 4 billion years and merge over the next few billion years to form a single galaxy. The galaxy product of the collision has been nicknamed Milkomeda or Milkdromeda.
Scientists predict a 12% chance that the Solar System will be ejected from the new galaxy. Such an event would have no adverse effect on the system and the chances of any sort of disturbance to the Sun or planets themselves may be remote.
However, our Sun itself is going to expand and get much brighter in the next few billion years. In approximately 5 billion years, it will turn into a red giant and will grow so large that it will engulf Mercury, Venus, and probably Earth. Earth will become uninhabitable long before the galactic collision. So, we better “evolve" and find ourselves a new home before these cosmic events occur ;)
Further Reading
- Hubble Telescope — hubblesite.org
- Hubble Wiki — en.wikipedia.org/...
- Hubble Twitter — twitter.com/...
- Galaxy and Nebulae photo galleries — hubblesite.org/… hubblesite.org/… eso.org/…
- Galaxies and Nebulae by Hubble (2017) — www.dailykos.com/…
- Galaxies and Nebulae by Hubble (2016) — www.dailykos.com/…
- The Lagoon Nebula — Celebrating Hubble Telescope's 28th anniversary — www.dailykos.com/…