In the Comfort Zone

The third planet from the sun, our Home; what made it so special? So ideal for the plethora of simple and complex organisms including us who can contemplate on “what makes Earth special”?


We have an atmosphere with right density, right pressure; the right temperature, and an ideal fluid to support life. But, is that all that makes Earth the right place for life to emerge? There is just one more essential parameter (which has made the other parameters possible). The distance from sun! A little nearer it would have been too hot, a little further too cold. Doesn’t that imply that for any given star if planets or moons happen to fall in this right place , then life might evolve on them? This region is called the Habitable zone or Goldilocks zone (after the same Goldilocks from “Goldilocks and three bears” who would have been part of your bedtime story as a kid) . But its not just the correct spot from a star that’s is essential for supporting life, but also the right location in the galaxy (galactic habitable zone). Near enough to the galactic center to have enough metals (to make it a rocky planet like ours) and far enough to remain protected from the high frequency radiations that is lethal to life forms similar to us (carbon based).

What makes such places hospitable? Simple! The perfect (or near perfect) temperature which can support liquid water, the one fluid that has changed or rather written the history of our planet. So when looking for earth-like life forms, it is such zones in the universe that should be the starting point for the search.
The above statement may be an oversimplification. For even on our own planet we have come across creatures called the extremophiles, living in deep hot sulphur filled vents, underneath ice sheaths in Antartica, in the darkest regions of ocean where no light penetrates; where one would have never imagined a possibility of existence of life. But even in these organisms survival has been possible because of liquid water( they have developed ways to keep water in liquid state within them).
Scientists studying the possibility of extraterrestrial life are trying to find and explore these comfort zones, where conditions seem to be like that on earth. Recently existence of a rocky planet in such a habitable zone has been observed for one of the close star (just 20 light years away) called Gliese 581.


The fourth planet from the star lies in the outskirts of this region. Intially the planet Gliese 581 d was thought to be too cold for supporting life, but around April 2009 it was confirmed that it lies on the border of habitability. All it needs to do now is make some green house gases, raise its temperature to become suitable for supporting life.

So as Goldilocks famous line goes (and reason why the name was given):
"This porridge is too hot," Goldilocks exclaimed.
So she tasted the porridge from the second bowl.
"This porridge is too cold."
So she tasted the last bowl of porridge.
"Ahhh, this porridge is just right!" she said happily.
And she ate it all up.
It has to be ‘just right’ nothing less, nothing more.

On being the largest

I have no idea how it feels to be the largest flower on earth. You will have to ask that to Rafflesia arnoldii. But I definitely know how it smells: like rotting flesh. Yuk! Growing up to 3 ft, there are lots of things that are weird about this plant or should I say flower. For, all that this one seems to have is a flower. No sign whatsoever of stems, leaves (No photosynthesis! Wasn’t it a defining characteristic of being a plant? Got to go back to my 5th std book and make changes) or true roots.



This one belongs to a group of plants called Rafflesia, all of which are parasitic, an endoparasite (grow within the host) to be specific. They specifically parasitize on a member of grape family called Tetrastigma. Rafflesia grow inside the grape plant’s stem penetrating its tissue through a thread like thing called haustorium (Seen in parasitic fungi as well) and absorb all nutrient from it (its like… u make the food, I will put a pipe and suck it out and use it to grow 3ft. Too much of an extravaganza for a parasite).
Once in a while, they put out a bud and after months it flowers, which lasts for few days (~7days). The plant (Rafflesia arnoldii) is unisexual (some species of Rafflesia are bisexual too), so there is a male and female version of the big stinker. Ahh! Now I guess I understand why it stinks! To reproduce it has to pollinate and for that it requires pollinators like flies. And rotting flesh attracts flies. Off comes a fly expecting a feast and Rafflesia sticks its pollens onto its carrier, which unknowingly will transfer the pollen to a female flower. Ingenious! But means by which its seeds are distributed isn’t known for sure, but seems like some shrews eat its fruit (doesn’t that stink?) and thus disperse its seed.

For all this planning and parasitizing, the plant is highly endangered. Blame it on habitat encroachment by humans. That apart there are lots of stuff about Rafflesia that makes them more prone, starting from their requirement of specific host (habitat specificity, occur only in the rainforests of Sumatra and Borneo in the Indonesian Archipelago). Being unisexual, it’s important that the male and female flowers be close by and that they should open around the same time. And to add to it, they flower only for few days, a time constraint as well. What sort of conservation do you think will work out for this flowering giant? (Grow the grape and put some flies and Rafflesia seeds!). Of so many bizarre designs that nature has come up with, Rafflesia arnoldii, is definitely one.

References:
http://www.parasiticplants.siu.edu/Rafflesiaceae/Raff.arn.page.html
http://en.wikipedia.org/wiki/Rafflesia_arnoldii

Dance of light

Through the vast sky she flies, spreading her light ; green ,blue, red, yellow and pinkish hue and the night sky becomes a play of light . She is “Aurora” the Roman Goddess of dawn blessing and bringing the night sky to life.

Well its not some divine glow lighting up the sky around the polar regions although it was believed so, It is Aurora Borealis( Boreas greek for ‘north wind’) in northern hemisphere and Aurora Australis (latin for 'of the south’) in the southern hemisphere. They are brought about by the solar wind particles(more on solar winds in the next post on Coronal Mass Ejection) colliding with the particles in the earth’s upper atmosphere exciting them .The excited particles relax by transferring their energy to others and/ or emitting a photon. Check out these beautiful pictures taken from places like Alaska and North Canada

And Aurora Australis captured by NASA's IMAGE satellite:

Although its occurs everywhere, being a phenomenon of upper atmosphere, it is more clearly visible as one goes farther away from equator and during equinoxes ( guess the reason!)

So what exactly happens when there is collision of solar wind particles with the atmosphere? It either ionizes or excites the oxygen and nitrogen atoms in the atmosphere(the two most common elements in the atomsphere). So if a nitrogen atom is ionized, on getting back an electron it emits blue light.

If it had just got excited, it emits red light and comes to its normal ground state.

The colour of light when an excited oxygen atom comes back depends on its initial excitation and the time it takes to come back to ground state. Green light is given if it comes down within three quarters of a second; red if it takes more time. If it gets to collide some neighboring atom and transfer its energy then none at all.

Do u think the colour is going to be altitude dependent? ( No, not your altitude , I mean the atom’s)

Auroras aren’t restricted to Earth. Solar wind and the planet’s magnetic field brings about a similar recreation of what we observe on earth. This ones from Jupiter:

I leave you gaping with these youtube video. May be try living the moments that we , near the equator don’t get to see.

References:

http://en.wikipedia.org/wiki/Aurora_%28astronomy%29