WHY ARE THERE SEASONS?
In what ways would Earth be different if there were no seasons? In many places on Earth, seasonal cycles dictate the rhythm and flow of life. Natural selection has blindly sculpted plants and animals to have adaptations that are perfectly in tune with seasonal variations of weather, sunlight and ecology.
This year I’ve been taking a photo on my phone whenever I walked through a certain part of the Australian National University. I’ve picked out three examples where you can see clear seasonal changes. But why does this kind of thing even happen?
A common answer people will give is based around the fact that the Earth does not orbit in a perfect circle around the Sun. They’ll tell you that we experience summer when the Earth is closer to the Sun, and winter when it is further away.
This explanation falls apart as soon as you consider that at the same time as you are in the middle of summer, for instance, people elsewhere in the world are in the middle of winter.
So can you explain it? Why are there seasons?
Road Map to Mars
In a year that has already seen announcement of plans to mine asteroids, the first privately funded spacecraft docking with the ISS, and engine testing on the Skylon project, plans for an even more ambitious project have emerged.
The Mars One program has announced a thorough road map detailing its plan to establish a human colony on the surface of the Red Planet by 2023.
How will this be paid for? They plan to turn the Mars One project into the largest media event ever by coupling the astronaut selection and training process to a reality TV show!
You can read their plan, but here is a summary:
- 2013: Mars One will build a replica of the Mars station on Earth for astronauts to train in. Astronaut selection process begins.
- 2014: Preparation for the Mars supply missions and communications satellite begin.
- 2016: The first supply mission will reach Mars, carrying food and other necessities for the future inhabitants.
- 2018: A rover will be sent to determine the best place for the settlement.
- 2021: The parts, supplies and major modules reach Mars, awaiting assembly by the first astronauts
- 2022: Water, oxygen and atmosphere production ready. The first settlers blast off from Earth on their voyage to Mars
- 2023: History is made as the first astronauts land on Mars, and link the settlement modules together and become the first extra-terrestrial settlers.
- 2025: The second group of inhabitants land. The occupancy of the Mars settlement is expected to reach between 20-40 people.
Such ambitious plans as this have usually fallen at one of the first two hurdles: funding and technology. However as we have seen with SpaceX, private firms have a great capacity for cash sourcing, and with the plan to turn the whole thing into a worldwide media event, Mars One might be well on their way to purchasing everything they need.
Technology wise, they have been very clever, and designed their whole plan around things which already exist and can be bought. In fact, all the landers and launchers are hoped to be supplied by SpaceX. This is great because it means that part of the money Mars One will be spending to explore space, will be spent by a company trying to explore space! This is exactly what we need for the space industry to flourish.
I really hope that this project gets going. They face some major hurdles - cosmic radiation poses a major problem for interplanetary voyages - but I’ll be waiting with bated breath to see how far this thing gets.
Good luck, Mars One!
This would be reality TV I would actually watch. The obstacles in the way of a plan as ambitious as this must be truly daunting, but just imagine if it happens. It would be all the awesomeness of the Moon Landing for a new generation, and perhaps the dawn of a new phase in human space exploration.
This is a rather famous nebula, because look at it- it is awesome. The image above is just one of many majestic pillars of gas in the nebula. It is six and a half thousand light years distant, and almost ten light years long. As mentioned in a previous post, the scale is hard to get your head around. You can get some idea from looking at that tiny isolated dark blob on the picture, near the bottom and left of centre. That blob is much much bigger than our entire solar system.
Many nebulae, including this one, are regions of active star formation- they are hatcheries for new suns. Our own Sun was born in precisely the same way.
If you want to check out the incredible detail in this photo, click here, though be warned- it is a gigantic file and may make your computer die.
When you look at an image like this, try to remember that it’s not just some abstract pretty colours. This is a photograph of a real thing that is actually out there. No one would believe you if you made these things up, but we live in a universe full of them.
Photo: NASA/ESA/Hubble Heritage Team
ILLUSION: SHADES OF GREY
Hold a finger between your screen and your face such that it blocks out your view of the dividing line between any two shades of grey in the image. Close one eye if you need to. The difference between the two shades should be hard to detect.
When viewing the image normally, the steps in colour are quite clear- the human eye generally picks up contrast quite well. We do however become far less able to resolve contrast between two fields if the intersection between them is obscured.
I created this image on MS Paint pretty quickly. I’ve been wondering whether making an image with with gradients of different colours (ie. green to blue, red to yellow) would work. Try to make one yourself, and post up a link to it.
Simple optical illusions like this are an interesting reminder of how easy it can be to fool our senses, and why some camouflage can work so well. This is why good science is so damn useful. The process of asking clear questions, designing careful experiments, and being open to criticism helps to ensure your are not being deceived (perhaps by yourself).
Sometimes you just can’t trust your own eyes.
INTELLECTUAL BADASS: MAURICE HILLEMAN
Time for another unflattering but necessary example of how amazingly important and clever people who have changed the world in a really positive way can go criminally under-recognised.
Reckon you could name the inventor of the measles vaccine? How about the person who came up with the vaccine for hepatitis A? Hepatitis B? Can you name the inventor of the one for chickenpox? Meningitis? Mumps? Pneumonia?
All seven of those vaccines were in fact developed by the same one man, Maurice Hilleman (the title of this post is a bit of a spoiler I guess). It has been quite reasonably suggested that he saved more lives than any other scientist of the 20th century. The measles vaccine has been estimated to have saved one million lives per year since its development. His work made it possible to virtually eliminate many horrific childhood diseases common fifty years ago.
He seems to have started powering up his intellectual badassitude at an early age, being caught reading Darwin’s On the Origin of Species during church. Crediting much of his early success to working with farm chickens as a boy, Hilleman created more than forty vaccines for humans and other animals. A strain of the mumps vaccine still used today is named after his daughter, Jeryl Lynn. Finding her coming down with the disease in 1963, he took a swab from her throat and headed to the lab right away, later producing the first mumps vaccine. He was just awesome like that.
Another one of his many achievements was integrating the measles, mumps and rubella vaccine into one shot, which is great for people like myself who dislike needles. Known as the MMR vaccine, this profoundly useful triumph of medical science has been at the centre of one of the most depressingly stupid and dangerous “controversies” I can think of. As Michael Specter explains in this excellent TED Talk, this is pathetic. Anti-vaccination activists do not see the terrible effects of measles, mumps or rubella because the vaccines they criticise have made them a thing of the past. This is the only reason people can be saddled with the misconception that vaccines are evil.
This is tragic irony turned up to eleven. This is weapons-grade facepalm material. It is sad and just plain silly.
Fortunately, however, we have researchers who today continue the struggle against disease just like like Maurice Hilleman did, using science to make things less awful for everyone.
Photo: Walter Reed Army Medical Centre 1958
Photographers always talk about perspective. It doesn’t get more perspective than this: first ever photo of the Earth and the Moon in the same frame, 1977. Taken by Voyager 1.
Could not have put it better myself. A pretty pair.
THE BIGNESS OF SPACE
Another image of the Tarantula Nebula. This one is a mosaic of ESA/Hubble Space Telescope photos. The image has been processed differently to the one in the last post, showing the rosy red glow of heated hydrogen atoms. Take a tour of the image if you want to explore interesting details.
I mentioned in the last post that the Tarantula Nebula is about 160,000 light years away. What does this actually mean? The vast distances between us and the things shown in these beautiful photographs are notoriously hard to get your head around, but I’ll have a shot.
Our Sun is on average about one hundred and fifty million kilometres away from us. This distance is the basis for the astronomical unit (au), a unit of length useful for dealing with distances between things in our solar system. Though 1 au (150,000,000 km!) is quite a massive distance, light from the sun speeds over to Earth in eight and a bit minutes (about 500 seconds). Light moves super quickly. If it can get from the Sun to Earth in eight-ish minutes, how far can it get in a whole day, or a whole year? A light year (ly) is the distance light travels through space in a year. This is a touch under ten trillion (one with thirteen zeros after) kilometres.
The Tarantula Nebula is in a region of the Large Magellanic Cloud, a kind of mini-galaxy that orbits our galaxy, the Milky Way. Current estimates put it at about 160,000 to 180,000 ly away from us. The Sun is just eight light minutes from us. So to get an idea about how far away that pretty bundle of glowing gas and newly-born stars in the image is, compare it with the Sun. Compare the light-times. Compare eight minutes with one hundred and sixty thousand years. Yep, space is really rather big.
Image of the Tarantula Nebula (also known as 30 Doradus and by the evocative and easy-to-remember name NGC 2070) captured by the amateur astrophotographer Marcelo Salemme.
Nebulae are awesome. You may have heard of the well-known Orion Nebula, and with good reason. It’s the closest region of massive star formation to the Earth, and is easy for people to spot in the night sky (close to Orion’s Belt). It has had many pretty photos taken of it, and was featured in the IMAX film Hubble 3D.
But the Orion Nebula is to the Tarantula Nebula what a hummingbird is to an albatross. It’s what a paper plane is to a Boeing 747, what your friend in film school is to Stanley Kubrick. All nebulae are amazingly vast in scale, but the Tarantula Nebula is just jaw-droppingly, face-meltingly epic. The Orion Nebula is only about 1500 light years away, and appears to the naked eye as a smeared dot of light. The Tarantula Nebula does not appear as bright, but it is roughly 160,000 light years away. If it were as close to us as the Orion Nebula, it would take up an area of the sky as large as sixty full moons. The glow from it would also mean that during the day, objects on Earth would cast two shadows. Like I said, epic.
Keep in mind this photo was made by someone who does this as a hobby. We’re lucky enough to live at a time in which telescopes powerful enough to see things like this are common. Most people who have ever looked up at the night sky on Earth were limited to doing so with their eyes.
Photograph of Buzz Aldrin taken by Neil Armstrong on the 20th of July 1969. The lunar module Eagle and Armstrong himself can be seen reflected in Aldrin’s helmet. Michael Collins, the third member of the Apollo 11 crew, remained in lunar orbit in the command module Columbia.
People often talk about the Moon as though it’s just a disc of light in the sky. But the Moon is a whole world. It’s a place as real as your kitchen bench or Madagascar. It has the Earth in the sky, just the way we have the Moon in the sky. It’s made of rocks and things that are just like many on Earth. It’s quite hard to get to, but people like you and me have been there, walked around there, played golf there. Two of them are in the image above.
Hopefully sooner rather than later humans can visit other worlds in this way, but until that time we can continue to send amazing robotic spacecraft on our behalf.