NGC 4594

NGC 4594 or the Sombrero Galaxy is a galaxy in the Virgo cluster around 28 million light years from us. It has around 700 billion stars and has a radius of 60,000 light years. If you look closely, you will realize that most of the other pin pricks of light in the image is yet another galaxy. Just think about these words and try to understand their meaning. “700 billion stars.” “28 million light years.” “60,000 light years.” The universe is too immense for our limited intelligence to comprehend its vastness!

NGC 4594
NGC 4594

What a wonderful world

Louis Armstrong – What a wonderful World

Sir Richard Attenborough – What a wonderful World

[Edited]

This is a truly a wonderful world and what amazes me is that there is so much to do and so much to learn in this wonderful world. Some days you come to know about the people who lived thousands of years ago and wonder what they thought and how they lived. You learn about conquerors and thinkers who through their sheer will changed the world.   Some time you come to know more about people like Andrei Sakharov and Sophie Scholl who stood up for what they believed was right in the face of overwhelming might of oppression. The courage that this would have required knowing that you and your family would suffer for your beliefs! Other days you peer into the space and wonder if there is somebody peering back at you. You wonder how far the space probes like Viking and Pioneer and New Horizons have gone and you also think about the scientists who made these amazing things possible. You just cannot imagine that human beings could do such things. There are frozen worlds in our solar system that may have liquid water and consequently life beneath their surface while there are planets on which its raining diamonds. Some days you come to know about some new discoveries like the possibility that life formed in the universe within a few millions years after big bang and you wonder whether there were galactic empires that rose and reached their zenith and spread across multiple galaxies and then collapsed millions of years before life began on earth. Some time you wonder if there are space stations at the edge of the solar system looking back at earth and relaying our thoughts and our progress to some distant empire who is worried about whether we are a threat. There were explorers who sailed the world’s oceans in boats that were powered by winds on their sails and there are aircraft carriers now that run on atomic energy and have 5000 people on board. 

I started this blog on 28th February 2010 with the reason for existence of this blog in a post titled Why.  After almost four years and 150 posts later, it seems to me that I have just scratched the surface of things that I do not know. Four years ago, words like Levant, Asia Minor, Polynesia, Mesopotamia, Kuiper Belt Objects, Milwaukee Protocol, Huaxia, Significant Figures did not make much sense to me. I would have guessed what they mean but I would not have been sure of it. But now the story is different. I also know that there would be infinite more terms that I have no clue about. As Donald Rumsfeld would have said, the known unknowns have increased but the unknown unknowns remains unfathomable. There is so much to explore!

Lets go exploring
Lets go exploring

Makemake and Eris

Makemake is the god of fertility and creator of humanity in the mythology of the Rapa Nui people of the island of Rapa Nui in Polynesia. Actually, Rapa Nui forms one of the vertex of the triangle that defines Polynesia. Rapa Nui is in the middle of nowhere, with the nearest inhabited island almost 2000 km away with the nearest continental point almost 3500 km away.

The Dutch explorer. Jacob Roggeveen reached the Rapa Nui island on April 5th, 1722, Easter Sunday. It was named Easter Islands, the name with which we know the islands popularly now. The islands are known for its large stone statues called Moai. I bet you have seen images of these statues and wondered what they are.

Makemake
Makemake

Moai

Moai

 

Polynesian triangle with Rapa Nui represented by 3.

Polynesian triangle with Rapa Nui represented by 3.

 Eris is the Greek Goddess of strife and discord. The story goes that due to her nature to cause discord, she was the only Goddess not invited for the marriage of Peleus and Thetis (Parents of Achilles. Remember Achilles as played by Brad Pitt in Troy?). She became angry and decided to crash the party. She brought with her an apple (Why does it always have to be an apple???) with “To the fairest one” written on it. This obviously caused trouble with all the other Goddess claiming they deserved it. The decision to adjudicate was put on Zeus who wisely delegated that to Paris, son of Priam (Paris – Remember Orlondo Bloom from Troy? The coward, useless guy??). Hera offered Paris ownership of all known world, Athena offered him wisdom and the abilities of the greatest warrior while Aphrodite offered him the love of the most beautiful woman in the world. In his infinite stupidity, Paris chose Aphrodite. Aphrodite gives him the love of Helen who is already married to King Menelaus of Sparta thus sowing the roots of destruction of Troy in the Trojan war.

In the month of March of 2005, 31st March to be precise (4 days after Easter Sunday), the team of astronomers at the Palomar Observatory of Caltech led by Michael Brown discovered the object seen in the below image.

Makemake through the eye of Hubble
Makemake through the eye of Hubble

This was code-named Easterbunny and it has a diameter about 2/3 that of Pluto with an orbital period of 310 years. With the astronomical naming convention of naming classical Kuiper Belt Objects (KBO) after mythological names associated with creation, Mike Brown and his team decided to name the object Makemake after the Easter Island God of creation. Its complete name is 136472 Makemake with the number being a sequential number.

In January of the same year, the same team of astronomers from Caltech also discovered what they called Xena or Planet X. The way these objects are discovered is by comparing successive images taken of the same region of space on successive days. Since the star move very slowly, they would appear stationary in these images while planets, dwarf planets and other objects that are closer would appear to move. Now the space is so huge, the objects so dim and the number of objects that are visible so large that this is a very difficult task. Sophisticated computer programs are written that compare these images and identify possible matches. These possible matches also number in thousands due to problem with telescope (eg, dust particle on mirrors), the imaging device (eq, photographic plates not properly handled, problem in digital cameras) etc that these matches would still have to be visually inspected by an astronomer to classify them as possible matches. Below is the image that shows Xena in three successive images.

Movement of Eris
Movement of Eris

 Now the problem with Xena is that it is larger than Pluto (around 12 km in diameter) and 27% more massive than Pluto. When the discovery of Xena was announced along with the discovery of Makemake, it created a huge controversy. Is Xena a planet? It is larger than Pluto and if size is the criteria then it should be classified as a planet and be Planet X or the tenth planet. Can Makemake be also classified as Planet, it is just 2/3 the size of Pluto? Can Ceres, in the asteroid belt, also classified as a Planet? These discoveries led to much “discord and strife” in the international astronomical community finally forcing the International Astronomical Union (IAU) to define planets as

(1) A “planet” is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.

(2) A “dwarf planet” is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.

(3) All other objects, except satellites, orbiting the Sun shall be referred to collectively as “Small Solar System Bodies”.

This resulted in Pluto relegated from the elite club of Planets to that of dwarf planets along with Xena, Sedna and Makemake. Due to the effect that Xena had, its discoverer Michael Brown appropriately named it Eris (136199 Eris).

Eris with its satellite Dysnomia
Eris with its satellite Dysnomia

 Fun Facts: Makemake has an orbital period of 310 years meaning it takes 310 years to complete one orbit around the Sun. Eris has an orbital period of 560 years (Aphelion around 97 AU) and at its most distance from the Sun, is almost twice as far away as Pluto is and believe me Pluto is far far away (Aphelion around 48 AU). New Horizons space probe, currently travelling at 14.8 km/s was launched in 2006 and will reach Pluto only by 2015. At its current speed, it can fly around earth in less than an hour. That should give you a perspective on how far away these objects are. Now the same Caltech team of Michael Brown also discovered 90377 Sedna. Now if you think Eris is very distant then Sedna is far, far, far, far away. Its aphelion is 937 AU, almost ten times as distant as Eris is and its orbital period is 11400 years! The last time Sedna was in the same position as today, humanity still had more than a thousand year to domesticate sheep and start agriculture (8000 BCE). 

Sedna
Sedna

Orbit of Sedna - Red ellipse is the orbit of Sedna while the purple ellipse is the orbit of Pluto. Note how Pluto's orbit intersect that of Neptune (blue circle) making Pluto nearer to the Sun than Neptune at some points of its orbit.

Orbit of Sedna – Red ellipse is the orbit of Sedna while the purple ellipse is the orbit of Pluto. Note how Pluto’s orbit intersect that of Neptune (blue circle) making Pluto nearer to the Sun than Neptune at some points of its orbit.

 

Panspermia

Panspermia is an hypothesis which says that life, at least single cellular ones, are abundant in the universe and that they piggy back on meteors and comets to seed new planets and moons. Panspermia does not tell us how the life was created, but just that the life once created travelled or travels to far reaches of the universe. Meteor impacts on a life bearing planet could eject material containing living organisms into space. These material form the basis of next generation of comets and asteroids and may contain living organism or at least chemicals that could form the basis for life.

Even on planet earth, we have found living organisms in extreme conditions. Certain bacteria can survive deep below the ocean surface under extreme pressure, others are able to survive in extreme cold, acidic or even vacuum environment. Variants of these bacteria could remain dormant on interstellar or interplanetary journey.

The Panspermia hypothesis do suffer from some serious drawbacks. The value of the Drake’s equation using the currently available data comes to around 10 which implies that there could be 10 civilizations in the Milky way with which we can communicate. But the galaxy is immense. Any travel between stars at the kind of speed that comets travels would take millions of years. It is unlikely that any organism, however resilient, would be able to survive that journey. Even if hundred meteors are formed from earth, the probability that any of them would contain organism that could survive the extreme temperatures of space, the vacuum, cosmic radiations, sun’s radiation is very low. That it would be able to escape out of the sun’s gravity and that of the gas giants gravity is even low. That it would be pointed at the correct planet, that could sustain life, of the correct star (Not too big and not too small) is infinitesimal. That it would survive the long journey reduces that probability even further (Half life of DNA is 1.1 Ma). Even after this the chances of the organisms to survive the crushing impact with the planet makes this probability even lower than infinitesimal. Absence of a thriving microcosm on Venus or Mars, which have environment similar to the early years of earth, indicates that Panspermia is unlikely. Organism that could have survived the arduous journey to these planets would have thrived there.

It is possible that life was seeded on planet earth by some extraterrestrial civilization (God?) and that we are or will in future seed life on other planet. Although, the space agencies do take extreme precautions to avoid contaminations, space crafts sent by us to other planets can contain microorganisms that can eventually lead to life on those planets. Directed Panspermia hypothesis states that an advanced civilization can create thousands, may be millions of meteor based space crafts, powered by solar sails and point them towards regions of the galaxy where new stars and planets are being formed. A little nudging by the onboard computer could take these meteor crafts to the correct stars and the correct planets to seed them. For a sufficiently advanced civilization that has spread to an entire star system, this would be comparatively trivial to achieve.

May be someday, buried deep below the earth’s crust, we will find a meteor with the remnants of the first life and the first computer on earth.

Kardashev Scale, Dyson Sphere and the Stellar Engines

How developed are we? How do we compare the technological capability of two civilizations?

One answer to this question is in terms of energy consumption. Russian astronomer Nikolai Kardashev proposed the Kardashev scale as a mean to measure the advancement of an advanced civilization. He initially proposed three levels.

Type I: A civilization that is able to harness all the energy of a planet. Thus if we are able to use all this energy we can come under the category of a Type I civilization.

Type II: A civilization that is able to use all the energy from a single star will be a Type II civilization.

Type III: A civilization that is able to harness the power of an entire galaxy will be a Type III civilization.

Type IV: There are multiple definitions of a Type IV civilization. A civilization that can harness the energy of the entire known universe or the energy of a Local Supercluster of galaxy. Workings of such a civilization would be pretty much indistinguishable from that of nature.

Carl Sagan proposed a simple mathematical formula to calculate the Kardashev scale.

K = (Log W – 6)/10

Where W is the total energy usage of the civilization. According to this, humanity is at 0.72 on the scale.

What would these different civilizations look like?

Type I: The largest nuclear bomb, Tsar Bomba had an energy output of 420 PJ. Which is much more than what humans consume (174 PW). The power output was 1.4% of Sun. (Joule is a unit of energy while Watt of Power. 1 Watt = 1 Joule/Sec.)

Type II: A Dyson sphere could be the kind of device used by a Type II civilization. Dyson sphere consists of orbital satellites orbiting the star. These constructs would then trap and use the energy output of the star. There are variants of this construct with one being a shell around the star that totally covers the star. Dyson sphere is a Class B Stellar Engine. More on them later. Construction of a Dyson sphere is an enormous, giganormous undertaking. The engineering and the amount of material required for the construction would be immense. The civilization may have to strip material  from the entire planetary system to construct such a device. Self replicating, smart machines in a post singularity world could build such a construct.

A Dyson Swarm

Type III: A galaxy spanning civilization similar to one in the Empire, Robot and Foundation series of Isaac Asimov perhaps falls under it though their energy use may not be as high as that of the entire galaxy.

Type IV: The civilizations in “The Gods Themselves” and the sentient intelligence at the end of “The Last Question” may be considered as Type IV civilization. Time Lords from the Doctor Who universe are also a Type IV civilization.

There are certain flaws in this classification. As a civilization develops technologically, it becomes more efficient and thus reduce its power usage. So a Type II civilization may in the course of time becomes so efficient that it becomes a sub Type II civilization.

Stellar Engines:

Stellar Engines are the technological constructs that uses a stars energy on a massive scale. There are three types of stellar engines:

Class A: Shkadhov Thruster. They are huge sails that uses the stars energy to nudge the star and with it its planetary system and accelerate it. These work at the time scale of millions if not billions of years.

Class B: Dyson spheres. Matryoshka brain (Matryoshka are the Russian doll inside a doll inside another doll toy). Matryoshka brains are Dyson spheres made for data processing. Thus you have a super massive computer utilizing the energy from an entire star to carry out its computations.

Matryoshka Dolls

Class C: A combination of a Shkadhov thruster and Matryoshka brain. Travelling Brainiac (Brainiac is the super intelligent artificial intelligence from the Superman universe).