Siddhartha Gautama taught that in order to see what matters we must first remove the ego from the equation. Nothing rips apart my ego or sense of self more than the Universe. The above photo is a compilation of the center of the Milky Way Galaxy in near-infrared, infrared, and x-ray from the Hubble Space Telescope, the Spitzer Space Telescope, and the Chandra X-Ray Observatory, respectively. As breathtaking as this image is with plumes of dust and gas, the bright star in the foreground, and all the distant stars and galaxies in the background, let’s take a momentary journey and see if we can’t have our consciousness expanded even more…
The second closest star to us is Proxima Centauri, some 4 light years away, meaning it would take us about 4 years traveling at the speed of light to get there. How fast is that? Stand in the dark facing a wall and turn on a flashlight, the speed at which that light hits the wall is the speed you’d have to travel at to get to the star in about 4 years time.
Proxima Centauri is a Red Dwarf, which means that when it dies it will not supernova, but instead the process of thermonuclear fusion will fade and as its nuclear core begins to cool it will turn into a Blue Dwarf, then fade into a White Dwarf and eventually become stellar material in space known as a Black Dwarf, a process that will take some three trillion years. Other stars with more mass are expected to supernova or even hypernova (equal to +100 supernova) anytime in the next million years (perhaps even tomorrow) and include Betelgeuse, Eta Carinae and IK Pegasi.
If that were to happen it would be like having a second sun or full moon in our sky, depending on the star and how far away it is from us. The largest known star by size is named NML Cygni and the most massive (heaviest) star is R136a1 which also claims the title for being the most luminous known to exist. Even though it’s the brightest in the known universe, it’s too far away to be the brightest in our night sky. The visually brightest star from Earth is Sirius.
This diagram shows the stages of a stars life. Depending on the mass of a star, various things can occur throughout its life-cycle. At the center of the diagram is the star forming nebula. All stars come into existence within a nebula, this includes our own star. In time stars fall away from the nebula clouds in which they are born, their gravitational pull will bring in dust and gas, which in time can form planets.
The above diagram lists examples of stars in each phase. The phases are listed in white lettering and the real stars that are currently in that phase are listed in yellow lettering. You can see that Proxima Centauri is the example used for a red dwarf star. Following this star’s path you can see it will become a blue dwarf, and eventually a white dwarf that is no longer active at its nuclear core and thus cooling into what is known as a black dwarf.
In this diagram you can see some of the prominent stars within our arm of the Milky Way Galaxy. The larger the circle, the larger the star. You can see that Sirius is the largest star nearest to us, which is why it is the brightest star in our night sky.
We exist within the Milky Way Galaxy, one of more than 50,000 galaxies and dwarf galaxies inside the Virgo Supercluster. Thanks to the Hubble Telescope, we know there’s about 100 billion galaxies in the known Universe, but this is only based on what we can see with current technology. In the future we may learn there are billions more. In the above diagram you see our more prominent and nearby galactic neighbors.
Most of these are smaller galaxies than our own, known as dwarfs. They are essentially just like larger galaxies, except that they have a lower stellar mass (fewer stars). You can also see the much smaller Triangulum Galaxy and the Andromeda Galaxy, the closest large galaxy from our own. Though it appears close in this diagram you have to realize that Andromeda is more than 2.5 million light years away. Think about that. It would take more than 2.5 million years to get there while traveling at the speed of light.
The entire Virgo Supercluster stretches for some 100 million light years. Within that there are some 200 trillion stars.
There’s a tiny little dot of yellow light that you can’t even see unless you zoom in southeast of the massive yellow globe in the center of this image of the Milky Way Galaxy, it’s marked “We Are Here” and that’s where our solar system is. The Milky Way Galaxy is what’s known as a spiral galaxy due to its shape. This logarithmic spiraling causes strands of stars, planets, dust, and gas. Each strand or section is known as an “arm” of the galaxy. We exist in what is known as the Orion Arm. All of those tiny lights you see are stars, you can also see the many dust and gas clouds.
That massive ball of yellow light in the center is a cluster of dust and stars. Inside that cluster is a supermassive black hole called Sagittarius-A. Compared to our Sun, it is 4 million times larger. Regular black holes are formed from dying stars, but astronomers still aren’t sure how supermassive black holes are formed. What we can speculate is that they are the remnants of something that existed before.
Nearly every known galaxy has a supermassive black hole at their galactic center. If you know what a black hole is, then you know that they have immense gravitational pull, so strong that dust, gas, stars, planets, and even light itself gets pulled in by the event horizon and cannot escape the singularity.
So what happens when objects or light are pulled into the event horizon of a black hole? Neil Degrasse Tyson describes it as spaghettification, essentially you are stretched on an atomic level. Ever play with silly putty and pull it apart until it gets really thin? Well it’s like that but on a molecular scale. What happens after that is still a mystery, but there are theories.
Based on models and simulations some scientists believe that once atomic bonds are pulled apart by the gravitational intensity and into subatomic particles by the singularity, they are then cast out into the universe as energy. What kind of energy is not known, but considering that nearly 70% of the known universe exists as dark energy, this may be the fate of all matter and light.
This graphic shows a scale of the mass of objects in space. If you can remember science class you’ll know that high mass means high density. As the mass of these objects increases, their density also increases. The center of a supermassive black hole is extremely dense, often described as infinitely dense. They defy what we know about the laws of physics as not only is the density of a black hole’s singularity infinite and its size infinitely small, but within that one dimensional point its gravity is infinite and space-time curves infinitely. This has led some astronomers to speculate that black holes are a point at which this universe connects to another universe that has different laws of physics.
Zooming out even further from the Milky Way and our location within the Virgo Supercluster, you can see where we are located in accordance to other superclusters of galaxies. All of those little specs represent galaxies. Several of these superclusters can be viewed from Earth using a telescope. In all, there are about 10 million superclusters in the known Universe.
You will also notice there are areas labeled as “voids” in the diagram. Aptly named, these voids are areas of the Universe that are empty of stars and planets. About 80% of the known Universe is made of these voids in space.
This is a timescale diagram. One of the most fascinating and mind blowing things about the Universe is that due to its vastness when you look at distant objects you are looking back in time.
The easiest example of this are the stars you see in the sky. Our own star, the sun, is so far away that it takes about 8 minutes for the light that erupts from it to hit your eyes or the ground at your feet. If the sun suddenly vanished we wouldn’t know it here on Earth for 8 minutes.
Other stars are so far away that even though you can see them twinkle at night, they may already be gone and the light you’re seeing is not the star itself but the light that came into existence hundreds, thousands, perhaps millions of years ago and is traveling through space towards us.
If you could travel the speed of light away from the Earth and had a telescope powerful enough to look back at Earth, the farther you traveled – the further back in time the Earth would appear. You could essentially travel back in time while traveling away from the Earth and see people living their lives who died hundreds and thousands of years ago, all the way back to the formation of the Earth itself.
The above diagram is showing the oldest known galaxy to exist at more than 11 billion years old, discovered by the Hubble Telescope. The Universe is estimated to be nearly 14 billion years old. To see into the Universe is to look into space and time, to travel through the Universe is to travel through space and time.