Pigeons on the Moon!

I have this distinct memory of seeing a Boa Constrictor in my backyard when I was a kid. It wasn’t just a garden snake – this thing had a distinctive grey diamond pattern and was wider than my head is round. My reaction was to climb to the top of our play gym as it slithered around the base. This wasn’t in some jungle community; nope, I grew up in the suburbs of Seattle.  

Current day me understands why my parents barely reacted to kid me when I described a gigantic snake in our backyard. I now logically know that this event never took place – it was a product of a powerful imagination. But to me, this was real as any other memory.

The human brain is incredibly powerful. So when the checkout person at Sprouts tells me that he has encountered aliens multiple times, my reaction is perhaps unique among astronomers. I understand that under extreme stress or even just normal conditions, we can make ourselves believe almost anything. And not just believe in a conspiracy theorist -schizophrenic – that crazy dude on the corner sort of way, but REALLY believe as I experienced with the Boa. 

This article is about a topic this same checkout person tipped me off to – Moon Pigeons. I decided to investigate further (instead of working on my actual work). Here’s the video I watched:

https://www.youtube.com/watch?v=jL7U1xgYz6w

(Video Credit: Science Channel)

If you watched the video, skip the next paragraph. 

Here’s what happened: Apollo 10’s headed to the moon. Their mission is to map the lunar surface in preparation for the famous moon landing of Apollo 11. But they have some issues with their computer system as they are trying to connect the lunar module with the command module. The TV footage of the orbit around the moon shows some strange patches of light that move across the screen. These aren’t just blips- there is a distinct shape that continues to move coherently across the entirety of the frame. Dubbed “moon pigeons” by the MSC structural engineers because there is no positive identification available, these objects are difficult to explain. Right after these moon pigeons appear, the computer starts working again and all else goes as planned. Ooooo, creepy.

Once the video was released to the public, multiple explanations surfaced.

This moon pigeon (which does look winged, and spaceship-like to me) is an extraterrestrial ship warning humans away from the moon. Some think that they jammed the computer system, some think they are benevolent and fixed it. Perhaps less imaginatively, some attribute the moon pigeon to a piece of debris from the mission or the leftovers of a previous mission. Some think it’s a chunk of ice. Nobody really thinks it’s an actual pigeon.

So I read NASA’s official report on the subject, entitled “Moon pigeons and other unidentified visual phenomena associated with space flight”. It was pretty dry, as scientific papers tend to be.  But their conclusions are that there are three main possibilities for the moon pigeon based upon the TV trajectory of the multiple sightings. They investigated the velocity of the object as it moved across the screen as well as the light reflected as the object tumbled through the sky in some cases. They conclude that the mysterious flying pigeon could be debris from an earlier mission, or ice, or internal/ external reflection from the window of the spacecraft.

Possibly a little boring, but that’s the official scientific report. And here’s my opinion – I will never believe the “official” report 100%, but I’ll lean more towards believing it than people’s opinions and raw speculations. If someone wants to publish a scientific peer-reviewed article on the alien nature of the Moon Pigeon, be my guest, and I would be excited to read it.

After all, I believe there’s life out there, just that we haven’t necessarily encountered it quite yet. We have a lot of exploring to do.

 

 

Godzilla Earth

Last week, some exciting new science made its way to the public stage. Exoplanet hunters (astronomers who search out planets outside of our own solar system) confirmed that they had found a planet, Kepler-10c.

Yeah, yeah, another planet to add to the record books. What’s so special about this one planet that sets it apart from the 1000 confirmed and 4000 planet candidates found so far with Kepler? After all, it gets a little tedious to see a new planet confirmation published every couple of days.

This planet is different. It is a rocky planet, dubbed the ‘Godzilla’ of Earths by the Harvard team who confirmed its properties. But it is 2.3 times the size of Earth?!?! Weighing in at 17 times the mass of Earth, this planet is baffling theorists. It was previously thought that a planet this massive couldn’t possibly be made of rock – it would collapse. Instead, only gassy planets could theoretically grow to be this massive.

So here we have an excellent example of how theory and observation work together in the scientific community! Observational astronomy (what I do) often completely obliterates (sticking with the Godzilla metaphor) the previous theories. This doesn’t mean that the previous science is inherently wrong. This just demonstrates that the scientific process is an evolving one, open to re-invention and innovation. 

Humbling, isn’t it?

The theorists are getting back to work…It’s now thought that the critical mass of a planet above which the planet MUST be made of gas to be stable might depend on how far the planet is from its star. Kepler-10c just happens to span the gap between what we dub “normal” terrestrial planets and “normal” gas giants. 

Not only is Kepler-10c a new type of “mega-Earth”, but it also orbits a star older than our own. Astronomers now know that rocky planets can exist at a time much earlier than our own solar system’s birth. This planet was born around 11 billion years ago (around 5 billion years older than Earth!).

In the mad search for life on exoplanets, this planet represents a whole new type of planet that could host life – because rocky planets are the best for this. And after all, it would be so sad to be all alone in this universe.

Death by Black Hole

“Hi, my name is Becky and I study black holes.”

Without fail, this is a great conversation starter, and inevitably I get inundated with questions almost immediately. Black holes are interesting, black holes are scary, and above all, black holes are hard to understand.

So in this post, I’d like to share a little of what I know about black holes and how they behave; my hope is that this will clear up some common misconceptions about black holes and provide everyone with their own interesting conversation points. 

We can’t know for certain, but astronomers estimate that there are between 100 to 200 BILLION galaxies in the universe. (A German supercomputer just predicted that there may be as many as 500 billion.) Most, if not all of these galaxies host what’s called a supermassive black hole. Just to be explicit, a supermassive black hole is probably best known as a song by Muse, but astronomers formally define a SMBH as the largest class of black hole. Weighing in at greater than 100,000 times the mass of the sun, these are the sumo wrestlers of the gravity well world and could pack a mean punch in the galactic dynamics ring. 

Above: NGC 4258 hosts a supermassive black hole at its center. The black hole is in the process of tearing apart the galaxy; in the process it produces jets (seen in pink). Credit: R Jay Gabany

So why haven’t we been warned of these alleged supermassive black holes? Can’t they suck everything in and KILL US ALL? 

It’s time to clear up some common misconceptions. Before I began my career in astrophysics, I believed that black holes only formed from extremely massive stars, that they suck anything and everything in like a vacuum, that they’re black, that they’re holes, that they are sometimes tunnels to another dimension or alternate universe, and that you can actually fall into one. None of these statements are true, and here’s why:

1. They only form from massive stars. 

Stellar mass black holes do indeed form from stars, but black holes form whenever the density of the mass/energy passes a threshold to trigger formation. If the Earth were the size of a nickel, it would form a black hole of the same mass. 

2. Black holes suck anything and everything in like a vacuum. 

Black holes behave themselves gravitationally – if the sun were a black hole of the same mass, the Earth’s orbit would be unchanged, we would just be rather chilly without the sun’s radiative energy. 

3. They are black. 

The term “black hole” is a misnomer since “black” indicates an absence of radiation, yet Stephen Hawking proved that energy leaks from a black hole in the form of virtual particles. This results in radiation and mass loss from the black hole. 

4. Black holes are holes. 

Hole is a two-dimensional term that doesn’t fit a three-dimensional universe. Black holes would be more adequately described as spheres.

5. They are tunnels to another dimension or alternate reality. 

This was a convenient solution to the Romulan problem in Star Trek, but has never been proven and may be impossible to prove outside of the science fiction universe.

6. You can fall into a black hole.

The technicality here is that you fall for an infinitely long amount of time as viewed from outside the black hole, so you never completely fall to the “bottom.” 

Come again? If you can’t actually fall to the bottom of a black hole, what would it feel like to fall into a supermassive black hole or just a black hole in general? Believe it or not, professional theoretical astrophysicists are paid to study this exact question. They push the boundaries of quantum field theory, Einstein’s general relativity, Einstein’s special relativity, classical mechanics, particle physics, and thermodynamics to derive a comprehensive theory of death by black hole. I will now compile their conclusions to describe death via SMBH. 

http://www.youtube.com/watch?v=3pAnRKD4ra

 

Here’s a great video about black holes in general – skip to minute 3 to begin the process of falling into the black hole. Physics can get pretty trippy sometimes! Around minute 6 he gets into some really crazy theoretical stuffy.

Credit: Vsauce

 

As the black hole approaches, you observe a spherical bending of light around it. This happens because the black hole is dense enough to put a dent in space-time itself. This means that light follows a curved path around the black hole to reach our eyes. You are also able to see an inner black region, the boundary of which marks the Schwarzschild radius, or the event horizon.

At first, you maintain a stable orbit around the SMBH, but once you pass the event horizon, you have passed a point of no return. This event horizon marks the point at which not even light (which matches the speed limit of the universe at 671 million miles per hour) can escape the gravity of the black hole. Past this point, physics starts to get weird. You notice that time, space, and light itself behave in strange, relativistic ways. I should probably mention at this point that you would not live long enough to pass the event horizon – black holes are energetic beasts so they are always surrounded by a radius of plasma and extremely hot particles known as the “firewall” – passing through the firewall would mean sure death. So already dead, you fall through the horizon and you notice the universe becomes brighter and brighter as space falls faster than light. At this point, you would die a second time via spaghettification – the tidal gravitational forces within a black hole exert more force on your feet than on your head. Neil DeGrasse Tyson once described the process of spaghetiffication: 

“Your feet start falling faster than your head does. That is a bad situation to be in. Initially it feels like cosmic yoga. It feels kind of good like a stretch. But you reach a point where the tidal force becomes so great that it exceeds the intermolecular forces that bind your flesh. The time comes where you snap into two pieces at the base of your spine.”

As you’re being snapped in half, and then halved again, you could look around yourself and notice that the universe has become two-dimensional. As you fall faster than light, the light above your head is stretched towards the red end of the spectrum (this effect is called Doppler Shifting and happens to the frequency of an ambulance siren as it passes by) and the light by your feet is blue-shifted as you rush towards it.

You are traveling so fast, that the light is shifted beyond the visible part of the electromagnetic spectrum, and you see only a narrow band of the universe around you – so in your last moments of life the world would be two-dimensional. Time is also behaving extremely strange at this point in your journey. Although it takes you a couple of hours to fall into a supermassive black hole (as opposed to a fraction of a second with a stellar mass black hole), to an outside observer you will never pass the event horizon. Since you are falling infinitely fast, time will pass infinitely slowly for you from your friend’s point of view. This is strange and unexpected, but black holes are the most gravitationally dense objects known in the universe, so they push physics of strangeness. So in the end, from your own point of view, if you don’t die from the firewall you will most certainly fall prey to the extremely painful process of spaghetiffication.

But don’t worry; it’s space so nobody can hear you scream

Reduce, Reuse, Recycle; How we throw away science

Check out this image:

This is an example of the resolution of a spy satellite. At three meter resolution, you can make out planes and building details. Imagine a resolution orders of magnitude better. Imagine a spy satellite with the ability to make out a coin on the roof of the white house. This resolution exists, and not only does it exist, but it’s been cast aside by the United States military.

A couple of years ago, the NSA declassified two spy satellites with these superior optics and gifted them to NASA. They are destined to be recycled and reused in the name of SCIENCE. These satellites are superior to Hubble, even after being stripped down to remove all classified technology by the military. BETTER THAN HUBBLE.

Hubble was touted as one of the technological feats of the late 20th century (after fixing the mirror problem of course). But it seems that simultaneously, the United States military was miles ahead, working on technology to look down and spy on our neighbors. Sometimes I just like to speculate on some of the technology that the US military has in orbit. And it’s not surprising that the military is eons ahead of Hubble technology; check out the budget imbalance in these two departments. This says a lot about priorities.

So why are we de-prioritizing science in the United States today? I think I know.

Alright. I’m about to go on a bit of a rant.

Recently, I’ve been thinking about the relevance of astronomy – deep stuff, but not unfounded, as people often ask, “Why should we fund astronomy when we have so much to fix here on Earth?”

Let’s take a look at the national budget:

 

This was Obama’s proposal for the fiscal year 2013. Guess which blob is NASA’s budget?

…

Image credit: pagef30.com

Yep, it’s that tiny blue blob. I’m not arguing that NASA’s budget is completely well-thought out and well-spent. But if the US government were to completely cut the NASA budget and put this money somewhere else, could it really solve all our problems on Earth?

If you really want to get into the relevance of astronomy, think about it’s role in advancing military technology, introducing novel techniques to industry and medicine, and its practical applications in daily life.

Astronomers developed the first CCD- this technology is now used in smartphones and spy satellites alike worldwide; NASA invented velcro to hold onto it in space – now we use velcro to keep kid’s shoes from falling off; Radio astronomy developed a technique that can be used for non-invasive cancer screening; We use astronomical objects to calibrate GPS systems; Astronomers developed fluid-based simulations that engineers use worldwide to keep us safe; Studying solar system planets have helped us understand the fragility of our climate here on Earth, need I go on?

Sometimes it’s too easy to forget about science. It’s just something that old white men do by themselves in their offices in their Ivory towers. But actually, if you stop and look around, science has transformed this modern world. The most compelling argument for me is given by Carl Sagan. If we stop investing our time and money in science, we stop exploring as a species, and we crush our curiosity. Without science we are giving in, we are regressing, and we are abandoning hope. As a society its healthy to have some knowledge of the world, and of the universe we live in. What a scary place this world would be without the creativity and knowledge we gain from pursuing astronomy.

So to end this rant on a good note, I give you Carl Sagan:

“We inhabit a universe where atoms are made in the centers of stars; where each second a thousand suns are born; where life is sparked by sunlight and lightning in the airs and waters of youthful planets; where the raw material for biological evolution is sometimes made by the explosion of a star halfway across the Milky Way; where a thing as beautiful as a galaxy is formed a hundred billion times – a Cosmos of quasars and quarks, snowflakes an fireflies, where there may be black holes and other universe and extraterrestrial civilizations whose radio messages are at this moment reaching the Earth. How pallid by comparison are the pretensions of superstition and pseudoscience; how important is it for us to pursue and understand science, that characteristically human endeavor.” – C.S., Cosmos

 

 

 

Gravitational Waves – Why is everyone so excited?!?

A week or so ago, physicists and astronomers alike got really exited by some published research out of Harvard. Astronomers claimed to have detected gravitational waves for the first time! Sounds cool, but hold the phone – these scientists are leaving us at the mercy of some complicated physics.

Here are the questions I hope to address in this post:

1. What is a gravitational wave?

2. How is this plot showing us the presence of gravitational waves?

3. Why is this at all important?

This plot demonstrates the polarization of the magnetic field. Polarization shows how light has been twisted due to the presence of gravitational waves.

1. What is a gravitational wave?

The first important point to understand is that a gravitational wave is not the same as a gravity wave.

A gravity wave is a wave that occurs as the result of gravity – you can see these in the ocean or in the atmosphere. They look like this:

Gravity waves in the atmosphere as the result of density differences in the air.

In contrast, a gravitational wave is a prediction of Einstein’s theory of general relativity. Gravitational waves are a theoretical way in which energy is radiated outward due to a disturbance in the curvature of space time.

What? In Einstein’s theory of relativity massive objects create a dimple of sorts in the very fabric of space time. So for instance, if there is a star orbiting around a black hole, this star will distort the dimple as it orbits, and as a result of this acceleration, energy will be radiated away in the form of gravitational waves.

Massive objects create dimples in the fabric of space time. When a massive object orbits another, it distorts the distortion of the other; this creates gravitational waves.

2. How is this plot showing us the presence of gravitational waves?

As gravitational waves propagate through space, they create a disturbance that looks like this:

This is a linearly polarized gravitational wave because it’s stretching the very nature of light, creating a linear polarization signal in the light detected.

But now it gets more complicated. This linear polarization is only from a specific kind of gravitational wave source. The gravitational waves theoretically predicted from inflation in the early universe are thought to have a circular “swirly” polarization in the magnetic field of the Comic Microwave Background. This is evident in observations and was detected to be much stronger than expected.

The Cosmic Microwave Background is from a very early period in our universe, and is basically equivalent to looking back at the infancy of the universe. This period of time occurred 1/10^35 of a second after the Big Bang. This is 1/(10+35 zeros). This is a an opportunity for physicists to observe energy beyond their wildest imagination, leading us right into point 3:

3. Why is this at all important?

For decades now, scientists have been attempting to pin down how our universe is behaving now and how its beginnings may explain this behavior. This discovery answers some important questions about inflation.

What is inflation?

Through observations, astronomers have been able to show that more or less, the present day universe is not homogeneous. This means it’s not the same in all directions. We see large clumps of galaxies called galaxy groups and superclusters. HOWEVER, from the observations of the Cosmic Microwave Background (earlier observations than this most recent study), we see that in microwave light, the CMB is more or less homogeneous. So how does an early homogeneous universe become the not homogeneous universe we live in today?

We also know that the universe is expanding – galaxies are moving away from us. And this expansion is accelerating. The theory of inflation states that the universe must have expanded extremely extremely rapidly in the first few nanoseconds to preserve our non-homogenous present day universe. This is a bit difficult to wrap your mind around so think about it like this:

Since matter is expanding faster than the speed of light during expansion, it cannot communicate with other patches of matter. Small quantum perturbations in a clump of matter may eventually lead to large scale structure, such as galaxy webs.

A galaxy web created through simulations of the behavior of cold dark matter – this matches our observations of galaxy web structure.

The new observations of the strength of the gravitational waves present in the CMB tell us that inflation was occurring and was much stronger than previously thought. This discovery will spur particle physicists and cosmologists alike to rethink their ideas of the strange physics of the extremely early universe.

Not only does this study tell us about the past, but it helps predict how the universe will develop from its present day structure. This sort of observational evidence from the BICEP-2 team at the south pole pushes the forefront of physics research both in terms of new powerful technology (which we usually find an application for in more practical pursuits) and by providing theoreticians with some fodder to continue their exploration of the physics that we don’t quite understand.

Good work at the south pole, guys!

It may be cold, but the air is thin and dry – great for astronomy!

The Sagan Series

A tour of the universe a la Carl Sagan.

The Cosmos Take 2

Fox news is remaking Carl Sagan’s iconic Cosmos series with the help of Seth MacFarlane (creator of family guy) and Neil Degrasse Tyson. It will premier on Fox on this Sunday.

Why re-create it?

There’s a lot to be said for science education through the glamor of a popular television series. Carl Sagan’s original series came out during the Cold War, when we as a human race were very focused on local issues; it’s hard to pursue astronomy when you’re going through bomb drills on a daily basis. His series strove to provide the viewers with a “cosmic perspective” in a time when the world needed a wider view of the universe.

Neil deGrasse Tyson hopes that in the present political climate, this series will remind viewers of our place as world citizens. In the emerging environmental crisis, the hope is that humankind can relearn its place in the universe and come to appreciate the grand scale of things.

Even if none of the above appeals to you, the technological advancements in filming have achieved such a level that this recreation of the Cosmos will be glorious in its effects.

Pale Blue Dot [This image was taken by Voyager 1 on its swing past Saturn in 1990]:

Carl Sagan said:

“From this distant vantage point, the Earth might not seem of particular interest. But for us, it’s different. Consider again that dot. That’s here, that’s home, that’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.

The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known.”

The (not really) Dawning of the Age of Aquarius

We all know about the song “Aquarius” from Hair. In popular culture, the dawning of the age of aquarius actually represents the new age movement, but it also refers to the dawning of a new astrological age.

The “age” of Aquarius refers to when the vernal equinox lines up with the constellation aquarius as seen above. What the heck is the vernal equinox?

It turns out that the vernal equinox is this somewhat imaginary point in the sky that defines where the sun is during noon on the spring equinox. If you want to be more technical, you can describe it as the point where the celestial equator intercepts the ecliptic, which is the sun’s path across the sky. 

It also turns out that the vernal equinox moves slowly around the sky (during the 26000 year precession period) and will thus slowly move from constellation to constellation. Right now the vernal equinox is in the constellation Pisces. It’s about to exit Pisces and head for Aquarius, but not for another hundred years or so. So much for Aquarius – it’s the age of Pisces!

Back in classical times thousands of years ago, the vernal equinox was in the constellation Aries. So due to the 26000 spin axis precession of the Earth (basically the Earth wobbling on its axis due to gravitational interactions with the sun and moon), the astrological signs that the ancient Greek astronomers assigned may not be entirely accurate.

Not only does precession affect the zodiacal constellations; since the Earth’s axis itself is wobbling, it will point towards different places in the sky over the course of the 26000 year period wobble. So in the distant future, our new north star will be Vega, not Polaris as we know it now.

 

So back to the zodiac and astrology:

Over 26000 years the vernal equinox will progress through all the 12 zodiacal constellations. For instance, in ancient Greece (2000 years ago, which is about 1/12 of the 26000 year full precession), the vernal equinox was between Aries and Pisces. Now the vernal equinox is just leaving Pisces, so it’s between Pisces and Aquarius (it won’t actually be the age of Aquarius for another hundred years). This means that the vernal equinox has progressed a full constellation width forward, and so some of the ancient predictions for your astrological sign may be dramatically off!

 

Extraterrestrial Life

I am giving a talk on the habitability of exomoons so I thought it would be cool to inform everyone on what I’ve learned these past couple of weeks. And this way I can distill my knowledge, and nobody else will have to read scientific papers.

I recently went to a AAS (American Astronomical Society) conference and the most popular and well-attended talks were those given by the Kepler team of astronomers. Right now in astronomy, searching for exoplanets is the “sexy” topic. Everyone wants to know how many planets they’ve found and how many of those may be habitable. I believe this is because we as a species are obsessed with finding life somewhere out there.

Because after all, it would be incredibly depressing to be all alone in this universe.

So the Kepler mission is uniquely tuned to look for Earth-sized planets orbitting other stars in the “habitable zone”.

What is the habitable zone?

The habitable zone is determined by the type of star the planet orbits. For instance, Earth orbits a normal star, so it can exist in its orbit without becoming so hot that the oceans boil off or so cold that they all freeze. But for colder stars, the habitable zone for planets exists closer to the star because the star is much colder, so the planet must be closer to stay warm.

This is all well and good for planets, but some astronomers have had the idea to extend this search to habitable moons of these planets. After all, look at our own solar system. Saturn and Jupiter have a plethora of moons, and its been theorized that some of these moons, such as Titan (Saturn) or Europa (Jupiter) may be habitable.

Here’s the distinction for moons:

Their habitable zone is determined not only by their distance from the star, but by their distance from the planet.

Tidal heating from the planet as well as a protective magnetic field and reflection of light and thermal emission from the planet can aid the moon in maintaining a stable climate.

But detecting these tiny (relatively small) moons is incredibly difficult – scientists have theorized that Kepler will only be able to detect exomoons that are 0.2 times Earth’s mass. This is a big moon! The largest moon in our solar system is Ganymede (Jupiter) and it is only 2% of the mass of Earth. So we would be looking for a class of moons that we haven’t even experienced in our own solar system!

Whatever the challenges, I firmly believe that with the next generation of precision ground-based and space-based missions, we may be able to detect the ever-elusive habitable exomoon (or exoplanet). Besides, wouldn’t it be cool if Star Wars’ Endor or Pandora or all those places in Star Trek were a reality? After all, astronomy is a lot like science fiction.

 

Dinosaur Demise

Did you know that a catastrophic asteroid impact on Earth 66 million years ago probably led to the evolution of Homo Sapiens?  

A team of scientists from Europe and the United States confirmed earlier this year that the Cretaceous-Paleogene extinction event (the event that led to the mass-extinction of 75% of the world’s organisms, not to mention the end of the dinosaurs) was caused by a giant asteroid impact.

Following this event, paleontologists have uncovered fossil evidence that a massive diversification of mammal species occured. This diversification would eventually lead to the evolution of humans!

So what happened? How does a 9 mile rock manage to kill off the most formidable predator?

The asteroid slammed into Chicxulub, Mexico, creating a crater 110 miles in diameter and releasing the energy equivalent of 100 teratonnes of TNT. This would be larger than the largest thermonuclear bomb ever detonated (200 million times greater than the Russian Tsar Bomba). The initial impact would have created mega-tsunamis the world over, but this is not the mechanism that killed off the world’s plant and animal life.

The impact would have created a massive cloud of dust that lingered in the atmosphere, blocking the sun’s energy. So the plant life would have died first, followed by the rest of the food chain. The dust essentially acted as a negative feedback mechanism, plunging the world into a global ice age. There were so many plants on Earth during this period, that it is believed the atmosphere had an overabundance of oxygen. Hence, scientists theorize that the explosion would have triggered fireballs in the atmosphere in pockets of oxygen.

The dinosaurs (cold-blooded tropical creatures) were caught unprepared. Only the smallest animals who were capable of hibernation or burrowing down below the surface where the ground was still warm survived. These were the equivalent of modern-day rodents.

This extinction event has always been loosely attributed to the Chicxulub crater, but until this year scientists have not been able to accurately date the crater. Previously, it was believed that the crater may have occured 300,000 years before the mass-extinction event, indicating that it may not have been the cause of the extinction. But now after recent studies, the crater has been dated to within 11,000 years of the event. This may seem pretty inaccurate, but when dealing with geological timescales, this is fairly accurate.

Cue my favorite part of the old fantasia movie: