Bats Can See

by Anupum Pant

While every teacher around the world is busy teaching their kids that bats are blind, the contrary is actually true. Bats aren’t really blind and they can see pretty darn well even in low light. In fact, their eyes work better than our eyes do in a dimly lit environment (eg. Moon light).

None of the bats’ 1100 species are completely blind. Although, there are a few which depend heavily on a technique called echolocation to navigate around objects which are near, they still have to use eyes to see objects which are far away. Additionally, most bats like to hunt in complete darkness (to avoid competition from other birds), so they use echolocation during such times [because eyes need at least some amount of light to be present]. The daylight hours spent by them to groom or sleep don’t demand much of their visual skills, but that doesn’t make them blind.

One way in which bat’s vision is poorer than our visual ability, is that they can’t see colors like we do. Everything they see is in black and white. This disability, if you may call it one, is compensated by their ability to detect light waves whose frequencies lie beyond the human visible spectrum. Flying foxes, however, which are actually bigger bats, can see colors.

So, simply put, bats can see, but they don’t have to use their eyes to hunt or move around. This makes your teacher wrong when he/she says chides you with the phrase – “Blind as a bat”

Bonus Bat Facts

  1. Bats don’t carry rabies. However, like humans, the disease affects some bats.
  2. Apart from vampire bats found in Mexico, Central America and South America, no other bats suck blood.
  3. Bats hunt insects above your head, they aren’t interested in your hair or your eyes.
  4. Bats can catch insects with their tail or wing membranes.
  5. Fruit bats are also known as flying foxes, they eat fruits.
  6. Bats collectively eat tonnes of insects and protect our crops.
  7. Some bats eat fish and frogs.
  8. Bats’ dung, is rich in nutrients. It is mined from caves, bagged, and used by farmers to fertilize their crops.

Echolocation: A bat echolocates by sending out streams of high-pitched sounds through its mouth or nose. These signals then bounce off nearby objects and send back echoes. By “reading” these echoes with its super-sensitive ears, the bat can determine the location, distance, size, texture and shape of an object in its environment. In some cases, a bat can even use echoes to tell insects that are edible apart from those that aren’t. – [Source]

 

Horror Movies are Good for You

by Anupum Pant

It is Halloween today and most of us must be busy making plans for the day. But if you’ve missed including a horror movie in your plans, after reading this post, you might want to consider putting it in the list.

Studies have shown that watching a horror movie can actually be beneficial to your health. In two separate experiments, scientists were able to record two different ways in which horror movies can be good for you. Of course, this shouldn’t encourage extremely sensitive people to force horror movies onto themselves. In spite of these proven benefits, pregnant women, old men, little kids and people with heart disorders must try to stay away.

Moreover, the benefits found, were not practically too big. So, if you are thinking of leaving your healthy diet plan and making up for it by starting to watch more horror movies, you are mistaken. But, scientifically, the discovery of such co-relations are considered as noteworthy.

The first study (increase in immunity)

Researchers suggest that while people watch horror movies, their brain secretes chemicals like dopamine, glutamate and serotonin. As a result, there is an increased brain activity, which makes the mind alert for a while. Additionally, threat signals that pass through the brain stimulate adrenal glands to produce adrenaline, which has an anesthesia like effect.

Secondly, a half-hour watch was found enough to boost the number of active white blood cells in their blood – they are responsible to keep diseases away. In the test, a first time watch of Texas Chainsaw Massacre by 32 men and women led to an increased immunity for some time. [Source Paper]

The second study (burns calories)

In another study conducted recently, scientists observed an average of 184 burnt calories among the people who watched The Shining (the 1980 thriller). Jaws took the second spot, with people burning on an average of 161 calories after watching it, and The Exorcist came third, with 158 calories. Top 5 calorie burning movies were as follows:

1. The Shining: 184 calories
2. Jaws: 161 calories
3. The Exorcist: 158 calories
4. Alien: 152 calories
5. Saw: 133 calories

Increased heart rate, muscular contractions, a surge in adrenalin, oxygen intake and greater carbon-dioxide output were the main reasons that  these extra calories got burnt. So, the next time you are watching a horror movie (working out), avoid popping popcorn. [Read more]

The Sun’s Unusual Behavior – Seen from Mercury

by Anupum Pant

The sun – as seen from Earth

For most of us living on Earth (closer to the equator), the sun has followed a simple path throughout the years. It rises, goes up at noon and then sets for rest of the day. It is a simple straight line for the complete year.
For people living a little away from the equator, things get a bit interesting. There, the summer sun at noon is overhead, but the winter sun is low at noon, not overhead. It isn’t very easy for a person living near the equator to grasp this phenomenon well. You’ll have to go there and see for yourself. Or simply, the simulator at the end of this paragraph will help you understand it better.
At poles, the sun almost moves horizontally for many days. It keeps on making a horizontal circle around you. There, it is day for 6 months and night for the next 6 months. [Here is a sun path simulator for Earth]

However, nowhere on earth, things get as interesting as they get in the skies of Mercury.

The sun – as seen from Mercury

On Mercury, the sun appears to briefly reverse its usual east to west motion once every Mercurian year. The effect is visible from any place on Mercury, but there are certain places on its surface, where an observer would be able to see the Sun rise about halfway, reverse and set, and then rise again, all within the same day. It is indeed an unusual performance which isn’t easy for us Earthlings to digest. [See animation in the next paragraph]

Why does it happen?

Let us consider a simpler analogy – some planets (like Mars), as seen from earth, take a similar path. [see the animation for Mars’s path as seen from earth]

The planets, including Earth, all travel around the Sun in a continuous orbit. We can see them make their way across the sky in a straight line usually. However, every now and then a planet appears to turn around. After turning around, it appears to move back the way it came. This is called a retrograde orbit and is caused due to the difference in speeds at which the planets circle the Sun.

So, as we see Mars do a reverse from earth, a similar motion of sun is observed from the surface of Mercury.

[Apparent Retrograde Motion – Wikipedia]