Archive for December, 2009
Joy to the world, the solstice is come! And with it, comes all the ancient traditions celebrating the season, and among them, the ones that involve the Christmas tree are particularly beautiful ones. Representing a renovated eternal life, with hopes for the future, it also represents the knowledge the ancients had of the very meaning of the solstice – that it may be the longest night of the year, but it’s also the day from which the days will start to be longer and bring plenty to the world. That’s perhaps one of the earliest and most important astronomical discoveries.
Well, since then we discovered a little bit more about the world and the whole Universe. How about looking at the Christmas tree through the light of a handful of this knowledge? Here is some food for thought:
- We now know more planets beyond the solar system than there are Christmas balls on your tree. The current count is at 358 exoplanets, and counting;
- If the planet was shrinked to the size of a Christmas ball, it would be an even smoother ball than the others. Geometrically: Mount Everest (8 km) or the Marianas Trenchr (11km) are small imperfections relative to the planet’s 12,000 km diameter. It’s an imperfection of less than 0,01%;
- “Earth is not spherical, it’s an oblate spheroid”, some Grinch may say. Indeed, it’s wider in the equator, but even then the deviation from a perfect sphere is of less than 0,04%;
- Still with the Christmas ball: if an 8 centimeters one represented Earth and the nearest ball represented the nearest known exoplanet – Epsilon Eridani b, 10.5 light-years away – then for the distance between them to be represented in the same scale as the size of Earth’s Christmas ball, the other one should be at approximately 630,000 km. Almost double the distance from Earth to the Moon. Epsilon Eridani b is quite far from here;
- Now, if the star at the top of the tree represented our Sun, 1,392,000 km in diameter, and the star at the top of your neighbor’s tree – say, 50 meters away – represented the nerest star system, Alpha Centauri at 4 light-years of distance; then the size of our Sun-star to be on the same scale it would have to be 0,74 micrometers large. From 1,4 million kilometers to more than 100 times smaller than the width of a hair, that’s how small the star should be for it to be in the same scale as the distance between it and the neighbor’s Christmas star.
It’s a very big Universe. It’s also a very old one:
- Let’s say your big, nice Christmas tree took ten years to grow. If the moment in which it was sown was the Big Bang, 13,7 billion years ago, and the rest of its history was compressed to present day, then the Christmas tree would have known the first primates only in the last few hours, and all our recorded history would have ocurred in the last minute. Ten years growing from a seed, and all our human adventures would have been instants played in a tiny little part of this huge tree full of balls and stars. The ten year-old Christmas tree can be seen as a version of Sagan’s Cosmic Calendar.
“Astronomy is a humbling and character-building experience”, noted Carl Sagan. “It is sometimes said that scientists are unromantic, that their passion to figure out robs the world of beauty and mystery. But is it not stirring to understand how the world actually works — that white light is made of colors, that color is the way we perceive the wavelengths of light, that transparent air reflects light, that in so doing it discriminates among the waves, and that the sky is blue for the same reason that the sunset is red? It does no harm to the romance of the sunset to know a little bit about it.”
It also should do no harm to the romance of the Christmas tree to know that it’s a conifer, that conifers date from the late Carboniferous, about 300 million years ago, which means that we don’t have to use too much of our imagination to picture a Christmas tree watching the whole of human follies in an instant. In a way they literally did.
Feel dizzy? Perhaps some Christmas Chaos will help you see the infinite that can lie in a Christmas tree.
Science can lead to awe inspiring thoughts, based on the real and awe inspiring observations of the world in which we live. It’s the greatest gift we have, and our greatest hope for the future.
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“The mystery began when a blue light seemed to soar up from behind a mountain in the north of the country. It stopped mid-air, then began to move in circles. Within seconds a giant spiral had covered the entire sky. Then a green-blue beam of light shot out from its centre – lasting for ten to 12 minutes before disappearing completely.
Onlookers describing it as ‘like a big fireball that went around, with a great light around it’ and ‘a shooting star that spun around and around’.
The Norwegian Meteorological Institute was flooded with telephone calls after the light storm.
[Daily Mail: Anyone for some Arctic roll? Mystery as spiral blue light display hovers above Norway]
There are even several videos:
As it turns out, despite initial denials from the Russians, all suggests it was a failed missile test. Norwegian news outlets already air the explanation, as the Russians did issue a warning that they were launching a Bulava missile at the right time and place to produce such spectacle.
Missile launches creating light shows are not that uncommon, but spirals? Those are somewhat rare, and are usually associated with rocket failure. The animation below illustrates what’s happening:
The exhaust gases are luminous because they reflect the sunlight at those high altitudes. And we are not speculating: in 2006, the almost exact same display happened with another Russian launch.
And two decades ago, even more spectacular spirals were seen in China:
If I saw that spiral in the sky, I would be baffled. Even after realizing it should be a malfunctioning rocket, because… it’s a giant light spiral in the sky!
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