So, here in England the Sun has been beaming down on us a lot these past few days.
On these lovely warm evenings it’s incredibly tempting to go out on a romantic stroll to watch the Sun set.
But in which one of these beautiful images has the Sun actually ‘set’ in?
A)
B)
C)
Well the correct answer is B.
Why?
Because although it appears above the horizon, it actually falls below it when the lower edge of the Sun appears to hit it.
The light of the Sun passes through the horizon at a decreasing angle, this bends the light increasingly as there becomes a greater amount air it has to pass through.
It’s a coincidence that the degree of light bending is almost equal to the Sun’s diameter.
This year (2011) Easter Sunday falls on April 24th. Last year it was April 4th.
So sorry guys, it’s a long wait until we can scoff those yummy eggs. But why does it keep jumping around? How do they decide Easter’s date?
Well, it’s all down to the moon. (Typical!) The date for Easter falls on the Sunday following the first full moon that appears after March 21st. This means Easter Sunday can fall anywhere between March 22nd and April 25th.
Sure, this little Octopus appears to have 8 legs. But if you’re to define limbs by how they’re used, an Octopus only has 2. They use their back 2 tentacles to propel themselves along the sea bed. They use their other tentacles (the 6 arms) for feeding and other tasks.
Another interesting fact about Octopi:
They contain about 2/3 of their brain in their tentacles. Because of this, a severed tentacle can crawl around and in some species it would be able to survive for several months! Wouldn’t that be a strange thing to come across while scuba diving.
I bet you didn’t think anything could live forever? Well you’d be wrong… theoretically.
The Turritopsis Nutricula is a species of Jellyfish. It’s a tiny jellyfish; about 1/5 inch wide, has a transparent body and has about 80 or so tentacles…
However, this particular Jellyfish has the astonishing ability to revert back to its polyp stage once it becomes sexually mature.
The Polyp stage of a jellyfish after the fertilized eggs have left the mother and fallen to the ocean floor, where they attach to a rock and start growing into what looks like a sea anemone. These polyps eventually form buds that break away into tiny jellyfish which then fertilize eggs and the process begins again…
So how does it change back you ask?
Their cells have developed a specific process of transdifferentiation.
Transdifferentiation, in biology, means that a non-stem cell can transform into a different type of cell, or when an already differentiated stem cell can create cells outside its already established differentiation path.
The Medusa (umbrella-shaped body) of the jellyfish is transformed into the polyps of a new polyp colony.
Well, how does it do that?
The Medusa reverts and the tentacles and mesoglea (the translucent, jelly-like substance that makes up most of the bodies of jellyfish) get gradually broken down into their component materials. The reverted medusa then attaches itself to the rock (or other hard surface) by the end that had been at the opposite end of the umbrella and starts giving rise to new polyps to form the new colony.
This process could potentially go on forever.
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