Tag Archives: Astronomy

How to: film canister rocket launch

8 Mar

Put this into the category of ‘fun things to do in the kitchen’ (while wearing proper eye protection).

The yard might be a better place for this one though, so you don’t put any film canister dents into your ceiling. When it takes off, it does have quite a pop (but equally it is pretty light).

What you need:

– 1/2 an Alka Seltzer tablet (aka sodium bicarbonate)
– 1 film canister
– 15mL of water
– wear eye protection

What you do:

– Put 15mL of water into the film canister (fill it about 1/2 way)
– Drop in the 1/2 Alka Seltzer into the water
– Put the lid on tight and give it a quick shake
– Put the canister down, upside down

Within a few seconds, the Alka Seltzer will partially dissolve. As it does this, it will give off some CO2 gas. As the pressure mounts, the film canister will get to a point where the lid can no longer contain the amount of gas inside.

When this happens, the lid pops off to release the pressure.



Thanks to Mr. Newton, we understand that when the pressure is released in a downward direction, the equal and opposite force reaction occurs, propelling the film canister up.

And in this particular example, I calculated the launch speed is 5.8m/s.

How I calculated this: the GoPro was shooting at 60fps, so each frame = 0.017 seconds. Looking at the footage, the canister moved about 10cm in a single frame. Using V=d/t, moving 10cm in 0.017s works out to 588cm/s or 5.8m/s.

Simple as that.

Modifications to try:

– Change the ratio of Alka Seltzer and water.
– Use vinegar & baking soda instead of sodium bicarbonate & water.
– If your camera doesn’t shoot at 60fps, just divide 1 by however many frames it shoots per second (e.g. if it films at 24fps, each frame is 0.04 seconds: 1/24=0.04).

Of course this little rocket doesn’t entirely do justice to how real rockets launch, in terms of fuel, ignition process, etc. – but it does provide a great little demo of Newton’s third law (with a little of the second law mixed in for good measure).

Jesse and I did this one on TV last week in the second half of our weekly Beyond The Sun space segment on Sun News Network, talking about a couple real-life rocket launches:

Intuition gives way to data in exploration of the Cosmos

2 Mar


Only the most anthropocentric among us would seriously argue that Earth, as part of a solar system, is a godsend.

Especially nowadays.

For me, it always made sense intuitively that our solar system is one among many – just as our star is one among many, or indeed our planet is one among many just in our solar system.

We’ve known for a while that our Sun is one amongst, literally, billions in the Milky Way alone. Thousands of years ago though this concept was intuition, and postulation. A lot of ‘what if?’ type statements were made about our Sun, in comparison to the twinkling lights of the night.

“What if we’re just a lot closer to this one, than to others, so it looks bigger and brighter?”

“What if it’s actually not all that different from others?”

Though there was no way to confirm these ideas – even if intuitively they did make a world of sense.

Through the advent of technologies – namely telescopes, invented roughly 400 years ago – data would eventually be provided to confirm the intuition that our little Sun was in fact quite a bit like all those stars that surround us at night.

(Of course to be accurate, the Sun is also dissimilar from many stars in terms of size, temperature, age, and so on — just as Mercury and Jupiter hold some traits in common, they are of course dissimilar in others.)

The Milky Way (Credit: A. Fujii / NASA)

The Milky Way (Credit: A. Fujii / NASA)

As time marches on, we find that in our solar system there is also a diversity of worlds: planets, moons, asteroids, comets – whatever classification you choose, there’s a multitude of those other bodies out there.

Again through technology – and again, namely telescopes – we’re able to confirm ideas that intuitively made sense to people of ages past: what if those wondering stars are other worlds?

In fact the word ‘planet’ derives from the Greek ‘asteres planetai’ – wandering stars – as the paths of the planets appears separate against the backdrop of the star field in our night sky.

Around the same time that we confirm there are other worlds around our star, folks start to wonder ‘what if those stars have planets, like ours does?’

It makes sense intuitively – just as the concepts of other Suns in the galaxy and worlds in our solar system makes sense.

What’s been lacking though is the technology to confirm this intuition – since let’s be honest, intuition alone is a very lousy way to do science.

We need data to confirm the hypothesis.

The first exoplanet – or extra-solar planet, aka a planet orbiting a star other than the Sun – was discovered in 1992. That’s only 22 years ago.

And in fact that 1992 discovery was of planets orbiting a pulsar. The first discovery of an exoplanet orbiting a main-sequence star (something loosely like the Sun) was in 1995 – not even two decades ago!

So on one hand, it might have been forgivable for people to argue that our solar system is unique. There had been, after all, no data to argue otherwise.

On the other, since the mid-90’s, there have been different techniques to detect exoplanets.

Though it wasn’t until 2009 that the rock star took the stage: Kepler.

(if you want to read all about the Kepler mission, go here – those details aren’t what this article is about)

With the Kepler mission taking centre-stage in our planet-hunting endeavour, we were finally able to take the first steps in confirming something that makes sense intuitively: many (if not most) other stars have planets orbiting them, just as ours does.

Exactly how many planets each star has, exactly the nature of those planets orbits, exactly the composition of those planets – and many other details – continue to be open questions in most cases. Though it’s worthwhile to note that in some examples, perhaps a dozen, we have a pretty good understanding of the answers to those questions.

Should it be surprising that we don’t have all the answers? Of course not. We have only confirmed that these things exist in the first place in the last couple decades.

Though as Kepler data continues to be unravelled (even if Kepler’s prime mission is kaput), I expect we will continue to hear announcements like the Kepler 715 release.

There are planets out there everywhere – and lots of them.

Their makeup is as diverse as the makeup of our solar system.

But now that we have data to confirm the exoplanet intuition, we need data for next big intuition: life.

And just has happened historically, we’ll start in our own solar system with Mars.

We have been investigating Mars from afar for hundreds of years. Over the last few decades we’ve been investigating it close-up. We’ve confirmed the presence of water. We’ve confirmed a hospitable environment (at least historically).

What’s next?

It’s time to go to Mars and search directly for life.

This search will primarily be one for ancient life, though it’s not out of the question that some microbes could exist underground near a water supply today.

Once again, this is an issue where it is intuitively plausible that Mars was home to life. We know the conditions were right, so why not?

But this is a big question, and again intuition isn’t enough – we need data.

To this end, the ESA’s Mars mission slated ford 2018 will have a direct search for life as it’s goal. NASA’s next large Mars rover is set for 2020.

I do, openly, speculate that this is another case where intuition will eventually be confirmed by data (whether it’s within the next few years or not though is harder to guess – Mars is a pretty inhospitable place now, and so evidence of past life might be hard to find – if it is there at all).

Speculation aside though, data can confirm for us that Earth is simply one planet amongst hundreds of billions – if not more.

This is a reality that may take some time to sink in, but it is an undeniable truth.

Just as it is equally true that the Earth is round, that we orbit the Sun, and that the Sun is but one amongst a vast ocean of stars.

A new photo of home: Earth as seen from Mars in January 2014

15 Feb

In March 2004, the Spirit rover on Mars captured the first image of Earth ever taken from the surface of another planet.

A couple weeks ago, NASA’s newest Mars rover accomplished the same feat, snapping a photo of the Earth and the Moon in the sky of another world.

The Mars Science Laboratory (aka Curiosity) captured this image on the evening of January 31, 2014 from inside the Gale Crater on Mars. The image was taken using the left eye camera of Curiosity’s Mast Camera (Mastcam) about 80 minutes after sunset. Mars and Earth were 160 million kilometers apart when the photo was taken.

You, along with everyone you have ever known or heard of, is here. (click image for larger version)

You, along with everyone you have ever known or heard of, is here. (click image for larger version)

(Click here to download 18mb TIFF file)

If (when) a human is on Mars and looks up into the sky, they’ll see Earth and the Moon as two evening or morning stars – similarly to how Venus appears in the evening and morning sky here on Earth.

In this photo taken by Curiosity, the Moon appears just below the Earth as a fainter, though still distinct, object.

I particularly enjoy photos like this due to rare the perspective it affords us. To be able to see our entire world, our “vast” civilization, take up only a few pixels in an image from another world is an important reminder that we are apart of something much larger.

It makes our problems and petty differences here seem less significant.

It provides inspiration for us to aim for bigger, better things.

Keep ’em coming, NASA. We all need to see things like this more regularly.

Earth & Moon - the bright objects in the sky - as seen from Mars by the Curiosity Rover on January 31, 2014

Earth, as seen from Mars, by the Curiosity Rover on January 31, 2014

And not to be forgotten is the famous Pale Blue Dot image captured by Voyager 1 from a distance of six billion kilometers in 1990.

Chang’e-3 lands on the Moon, successfully deploys Yutu rover

14 Dec
Yutu drives off Chang'e-3 lander successfully

Yutu drives off Chang’e-3 lander successfully

It’s the first Moon landing in my lifetime, and if you’re under age 37 it’s the first one in your lifetime as well.

On Saturday, December 14, 2013 at 8:11 a.m. EST the robotic Chinese lander Chang’e-3, and it’s rover named Yutu, touched down safely on the lunar surface. This historic landing is the first Moon landing for China, making them only the third nation to safely land a probe on our closest celestial neighbour.

The Yutu rover successfully separated just after 4:00 p.m. EST.

This is the first object to safely land on the Moon since the Soviet robotic mission Luna 24 landed on August 22, 1976.

The last time humans were on the Moon was December 11-14, 1972 during the last of NASA’s Apollo missions, Apollo 17. This also places added historical significance on today’s date – December 14 – as it is both the last time a human was on the Moon in 1972, and today’s first Chinese landing.

Chang’e-3 launched on December 2 and then took about four days to reach lunar orbit. From December 6-14, the orbit was being adjusted in order to setup today’s descent and landing.

Today’s landing, considered one of the biggest challenges of the mission, consisted of approximately 12-minutes of powered descent towards the surface. When the lander was just a couple meters above the surface, the engine shutdown as planned. This allowed the lander to float down safely, but also minimized the amount of dust that would have been kicked up if powered flight continued all the way to the surface.

After landing the vitally important solar panels deployed successfully and began powering the lander and rover.

When Yutu was deployed, it drove forwards onto a small ramp and was the lowered to the surface. All six of it’s wheels then drove off the ramp and onto the lunar surface, leaving clear tracks behind it as it slowly moved along.

The touchdown happened in an area of the Moon known as The Bay of Rainbow.

China’s first two missions to the Moon, Chang’e 1 and 2, were both orbiters. They had no intention of landing. Chang’e-3 was the country’s first attempt at landing.

In Chinese mythology, Chang’e is a goddess that travels to the Moon. Yutu, or Jade Rabbit, is her companion.

The Yutu rover is expected to operate for about three months while the Chang’e-3 lander should operate for about one year on the surface of the Moon.

This article by Harrison Ruess also appeared on Sun News Network.

Looking down towards the lunar surface from Chang'e-3 during descent

Looking down towards the lunar surface from Chang’e-3 during descent

View from Chang'e-3 shortly after touchdown

View from Chang’e-3 shortly after touchdown

Yutu will drive onto the ramp to be lowered to the surface

Yutu will drive onto the ramp to be lowered to the surface

Yutu on its way down to the surface

Yutu on its way down to the surface

Yutu exiting the ramp and onto the surface of the Moon

Yutu exiting the ramp and onto the surface of the Moon

Yutu on the surface of the Moon

Yutu on the surface of the Moon

The control room

The control room

The landing process

The landing process