Category: Astronomy

Mars Mission Decoded To A Four Year Old

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Vasvi declared that she wanted to go to Mars, and I had to decode a lot of things for her to explain the differences between San Francisco and where she wants to go. The best way to overcome challenges is to face them and start thinking about how this generation needs to prepare.

Feature Simple Speak
Gravity (3.71 m/s2) You’ll walk as if you’re light-hopping, you’ll weigh only 1/3rd; Jumping from a rock will feel slow motion (you’ll take about thrice as more time to fall)
Diameter (6794 km) Will take half the time to get around Mars, map scales will be larger
Sun’s luminosity (40%) Brightest days will look like very early mornings
Atmospheric Pressure (600 Pa) Water will boil at about 0 degrees C, right where it freezes here on Earth (see this table)
Temperature (-60C) Really cold as compared to most of earth
Two Moons As fascinating as this sounds, these are really very small rocks around Mars, as compared to our moon and have minimal effect on Mars. In reality, you can’t see a large moon on Mars (its pretty empty).
Orbital Period (687 Days) Summers will last about 6 months, and every other season will be longer than here. Calendars will have longer months and longer years there.
Life (unknown) There are no trees, no bees, no butterflies, no birds and no flowers. Its pretty empty from a living creature perspective.

To a child’s mind, the differences are not as extraordinary as it is to adults. They are still linking to what is supposedly normal.

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Red Moon During Lunar Eclipse

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This Moon (Lunar Eclipse)is a photograph (credits to Hemant Hariyani) taken during a lunar eclipse. Besides being a very beautiful sight, there’s a curious orange tinge on the lower left quadrant of the moon. My curiosity lead to the moonzoo (please search for the terms “blood red” on that page to see their reason) – which explains very briefly the cause of this. While discussing on a list, I realized that it’s confusing sometimes to visualize how exactly this happens – so I drew a diagram to get this straightened out.

Reason for the moon's blood red (orange) color during lunar eclipseRefraction causes light to bend – and when different colors of white light bend at different angles, that causes light to split up; the very cause of rainbows. This is enough theory, the rest is self explanatory in the diagram beside this text. As you can figure out, light from the sun, reflected refracted when passing through earth’s atmosphere – falls on the moon (and since only longer λ [red] reach out) it looks orange (or blood red).

It’s imperative to note, that the cause of this blood red color is very different from the cause of the blood red color we see when the moon rises on certain nights. That blood red is caused because the light coming from the moon gets scattered when passing through the earth’s atmosphere (more so, polluted atmosphere), which causes the red waves to fall on our eyes and make the moon look red. That is when the light from the sun gets reflected back on earth and on it’s way to our eyes, we see red (the whole thing looks red – unlike this phenomenon).

Dhanushkodi: Annular Eclipse

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Moon's shadow on EarthWas my first time at an annular eclipse (with 100% contact – have been in partial contact once in 2005). Just to be clear, an annular eclipse, contrary to a total eclipse, does not induce darkness due to the increased distance of the moon from the earth. To understand further, you might want to see this image (preview on the right).

Pavan (an active volunteer of BAS) was accompanying me and Raghu on this trip. We drove to Dhanushkodi via Madurai and Rameshwaram (the oncoming two/three wheelers on your side of the lane deserves a separate post). We almost got killed by an oncoming Ambulance. A day’s stop in Madurai on Jan 14 and Jan 15th saw us in Dhanushkodi (DKD). DKD is right across Pamban bridge, some 10 Kms from Rameswaram. It’s a small island, surrounded by the ocean on two sides and extends to the last point of India that just touches Sri Lanka.

Annular Eclipse Phases - (click to view larger: in a new window/tab)

Contrary to expectations, DKD was free of an enormous crowd. The Tamil Nadu Science Society was organizing an event there (and quite a few folks from Assam – the Guwahati Planetarium, Gujarat, Bengal etc. were to be seen). Photos were being clicked as the “Media” approached us and we shyed away. Though we were carrying a telescope, due to lack of a filter we could not set it up and missed  the oppurtunity to use it. Pavan got a filter for his camera right on time (though I carved out something with an X-ray sheet, but the mylar sheet filter was definitely a better bet).

First contact of the eclipse was at 11:15 AM – as we put on our eclipse viewers, the sight was stunning.  The intensity of the sunlight decreased by as much as 75% (approximately) and the temperature certainly decreased by at least a couple of degrees (if not more). The sea wasn’t very rough, but the tide certainly had increased a lot more than what it was in the morning.

At about 1:20pm, we saw the ring – a beautiful sight as I kept gazing at it. There’s still a lot of light around you, just that it is white and not the usual yellow light and the intensity is nothing like a sun in a clear sky. The sky was spotless during the maximum eclipse around the sun, but it felt like there’s a cloud covering. Something very unusual, but a characteristic property of an annular eclipse on the ground. To understand how the eclipse traces the path on the ground, see this image.

We came back to Rameshwaram, stayed on till night and hopped back home the next day.

Interestingly, Raghu pointed out that I ended up following the popular superstitous Hindu activity of:

  1. not eating anything during the eclipse (though I drank some water and ate peanuts – which he discounts as: “even monkeys eat them“),
  2. taking a bath post-eclipse (we found a room at Rameswaram only in the evening, so I took a bath ASAP),
  3. visiting a temple post-eclipse (we went to hog – but couldn’t find anything since Rameswaram halts between 5pm and 6.30pm – so we had to go into the temple to make the most of our time)
  4. eating only after a bath (we were forced to take another 22 baths in the Kunds in the Rameshwaram temple – and then we hogged Dosas).

Heh, I broke (1) though, while Raghu/Pavan somehow broke (1) and (2). So glad I am.

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