The Day the Sky will Fall - Colliding with the Andromeda Galaxy

Meet Andromeda, a beautiful spiral galaxy (you must see this) bigger than our own, approximately 2 million light-years away. Andromeda is blue-shifted, meaning it’s heading our way, however this does not mean it will definitely collide with our Milky Way, since the galaxy's tangential velocity is unknown. Galaxies colliding is a frequent event within galaxy groups, and there are signs that Andromeda has already swallowed several other galaxies in the past. In Greek mythology, the young princess Andromeda was pretty helpless, needed to be saved by Perseus from the sea monster sent by Posiedon to the coast of Ethiopia. In real life, it seems like this girl can take care of herself pretty well...

If we are on a collision course, this neighbor heading our way at a relative speed of about 140 kilometres per second, should pay us a visit in about 2-3 billion years, even before our sun will start turning into a red giant, boiling our oceans and evaporating our atmosphere in the process. In the aftermath, it is predicted that both galaxies will change beyond recognition, merging to form a new giant elliptical galaxy – sometimes being referred to as the “Milkomeda” galaxy. And what will become of our solar system in the case of a collision? The chances of a physical impact between stars, planets or moons are very low, since the majority of galaxy space is actually empty, but the enormous gravity pull will take its toll for sure. One option is that our solar system will be thrown away to a higher orbit around the new center of Milkomeda. Another option is that we will be totally ejected from the galaxy to drift alone through the vast empty inter-galactic space. Another cheerful option is that we will be thrown toward the core, where a super-massive black hole lurking behind its event horizon will devour us.

No matter how it will end, it will be a spectacular sight to watch. And you thought our current night sky is beautiful… Just think of how it will look in 3 billion years, when Andromeda will stretch its spiral arms to fill the entire black canvas above...

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p.s. If I’ll drop two balls of different weights from the Leaning Tower of Pisa, will I be sued for polluting?

Forever Young

This is an Ankh - the ancient Egyptian symbol of life. They believed in immortality and the afterworld that was filled with comfort and happiness, and were probably anxious to get there. I don’t. This is why I write this post.

Life expectancy is constantly rising; the world average is almost at 70, and in some modern countries it is already above 80. Still, a person living for more than 90 years is very impressive, and reaching 100 is extremely rare. What would it take to break this 2 digits barrier? What would it take to break the 3 digits barrier?

Surely, heart attacks, strokes, diabetes, and many other problems need to be addressed, but assuming all these are solved, can we live to be 500 years old?

First, we’ll probably need to address the “end replication problem”. The Telomere is a region at the end of each chromosome (in humans it’s a repetitive sequence of TTAGGG). Because of some complex mechanical reasons, every time the DNA is replicated, the Telomeres at the ends of the chromosomes are shortened, until the point where there are no more Telomeres left, and the DNA is no longer able to replicate itself. Surely, this limits our life span, since the length of the Telomeres only decreases from the moment we are just a single cell within our mother’s body. Note that cancer cells can overcome this problem to create cells that can replicate indefinitely, but we need to solve this problem on healthy cells as well.

Assuming we’ll solve the Telomeres issue, DNA damage seems like the next big problem to overcome. Our DNA is constantly getting corrupted by random mutations; additions, omissions and dislocations of DNA sections; viruses inserting their DNA sequence into ours; attacks by free radicals; cancerous materials like those found in polluted air and cigarette smoke; electro-magnetic radiation in sunlight (UV radiation), X-ray and radioactive materials. Your perfect DNA is accumulating damage from day one, eventually resulting in problems like cancer.

We can try and fix the damaged DNA by applying sophisticated state-of-the-art gene therapy technologies, but I’m afraid we’re many decades (centuries?) away from a total understanding of our DNA, and no one really knows what will happen if we’ll start messing with it. It seems like our best chance lies in laboratories researching stem cells (cells that retain the ability to renew themselves through cell division and can differentiate into a diverse range of specialized cell types). I’m talking about rejuvenating the whole body (mind included). A few years ago, I saw a documentary about trying to treat Parkinson’s disease by injecting stem cells into a patient’s brain. It only helped to a small degree and for a very short period of time, but still it was very impressive. Stem cells might be the Holy Grail in our quest for partial immortality.

It will take a few decades, but the 2 and later 3 digits barriers will be broken - I promise. There is a common Hebrew greeting announced on every birthday that goes something like “may you live 120 years”. I foresee a day when this blessing will turn into a curse.

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p.s. Money’s green - should they test for color blindness when hiring for NYSE?

Doomsday Rock Coming Your Way at 15 Miles per Second

Somewhere on December 2004, Bruce Willis and Ben Affleck drilling and blowing up an asteroid in space stopped being amusing. A newly discovered asteroid was thought to be on a collision course with Earth; predicted impact energy: 400 megatons (~30,000 Hiroshimas); ETA: April 13, 2029. This asteroid was named ‘99942 Apophis’ after the evil demon, the deification of darkness and chaos in Egyptian mythology. Although later on, a more precise calculation revealed that this 300 meters (1000 feet) rock will wave us hello from about 25,000 kilometers away (VERY close) but will not impact our beloved blue sphere, it seems like the night sky will never be the same again.

A doomsday meteorite hitting the Earth will release energy many times greater than all the nukes in the world. It will vaporize several countries on impact, melting the Earth’s crust and igniting every flammable material. The survivals will witness world wide volcanic eruptions, earthquakes and firestorms. The oceans’ acidity level will drop to that of a battery acid and the sun’s light will be completely blocked for years. All plants and animals will die, transforming Earth into a lifeless desert. The good news – it should be suitable for life again in a few thousand years.

So what could we do? The one thing you don’t wanna do is nuke it Armageddon-style. If the asteroid is hard, then this will only break it into many smaller now radioactive pieces that will hit Earth on multiple locations. If it is softer, the blast’s energy will be absorbed, so nukes will have almost no effect at all. Some methods suggested are to use a spaceship’s gravity in order to slightly affect the asteroid’s path, use a giant mirror to focus the sun’s heat (to melt one spot of the asteroid to create a jet stream deflecting the asteroid), pull it, push it or ram it. Some of these might actually work, we just need a tiny change in course or speed, but we must have an early warning - decades in advance.

Currently the most dangerous known rock in space is ‘1950 DA’ that should drop by to say hello on March 16, 2880, but there are thousands of unknown asteroids and comets that may impact Earth in the near future. It’s not a question of ‘if’, it’s a question of ‘when’. It can happen in a million years; it can happen by the time you’ll finish reading this post, but eventually - it will happen.

The biggest threat to human race, the one thing that can wipe us out completely and make us extinct, emmm… I’m sure it’s top priority. Or is it? Currently, about 30% of the sky is not even surveyed! To quote astronaut Ed Lu from the Johnson Space Center “The number of people world wide who are working actively on this problem is enough to staff one shift in a McDonald’s”. Good night, sleep well; the planetary defense is in the hands of 4 kids with build-your-own-telescope kits.

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p.s. The Sun will die in 5 billion years. Good! I hate sunscreen!