| |
Quirks & Quarks April 12, 2003
Audio Files:
Real Audio Files: Listen in real time or download it here.
[Available Saturday 2 hours after broadcast].
A New Kind of Rocket Science
Listen to an mp3 of this topic or download the Ogg file. (what's
ogg?)
Electric thruster from NASA's Deep Space 1 mission. Courtesy of NASA |
For our fifty or so years in space we've been using chemical propulsion - essentially fire - on our modest little missions around the solar system. Now, finally, we're at the point of moving beyond chemical propulsion for space travel. We'll soon be exploring using an array of advanced technologies more efficient and effective than chemical rockets. Some of these ideas aren't new. Dr. Stan Borowski, Advanced Concepts Manager at the Space Transportation Projects office at NASA's Glenn Research Center works on nuclear thermal rockets. These are similar to chemical rockets, but are twice as efficient, and have been touted as the best choice so far for a human mission to Mars.
An even more efficient idea is using nuclear generated electricity for thrust, with an electric thruster. Joseph Nainiger,Nuclear Systems Program Lead at Glenn Research Center, thinks this could be the way we can send probes to the outer planets that could use their efficient engines to just drive from planet to moon to planet.
According to Les Johnson who leads the In-Space Propulsion Technology Project at NASA's Marshall Space Flight Center, there are systems that may fly soon that need no propellant at all. They harvest the energy of space itself. The plasma sail uses magnetic wings to capture the solar wind for thrust. And electrodynamic tethers and momentum exchange tethers harvest the energy of the earth's magnetic field for thrust.
While these ideas might allow us to explore the solar system more effectively, according to Mark Millis, the founder of NASA's Breakthrough Propulsion Physics Program, they won't take us to the stars. For that, we're going to have to find something brand new in physics - a way to harness vacuum energy, or use dark matter, or perhaps discover a warp drive. All these things, however, are more dreams than reality.
Related Links
Today In History - Yuri Gagarin
Listen to an mp3 of this topic or download the Ogg file. (what's
ogg?)
Coincidentally, as we look to the future of space flight, we also want to look back - to the beginning. Today is actually the anniversary of the first manned flight into space. It was on this day, April 12, 1961, that Major Yuri Gagarin became the first human to orbit the Earth. Gagarin was launched aboard a spacecraft called Vostok 1, from the Baikonur Cosmodrome, in what was then the Soviet Union.
After a single orbit that lasted just 108 minutes, Gagarin re-entered the Earth's atmosphere and landed on ground. The world first learned of his historic flight with this announcement on the shortwave service of Radio Moscow: Yuri Gagarin died tragically in an airplane accident in 1968. He is considered a Russian hero and will always be remembered as the first human to leave this planet.
Gorillas Will Be Missed
Listen to an mp3 of this topic or download the Ogg file. (what's
ogg?)
African Gorilla courtesy Dr. Peter Walsh |
Peter Walsh at the Department of Ecology and Evolutionary Biology at Princeton University. He and his colleagues have discovered that in Central West Africa, where 80% of Africa's gorillas and chimpanzees live, hunting for "bush-meat" and Ebola have devastated ape populations.
They estimate that since the early eighties at least 56% of the ape population has been lost, and the losses are accelerating. It's a catastrophe for our closest animal relations.
Related Links
Sexy Swordtails
Listen to an mp3 of this topic or download the Ogg file. (what's
ogg?)
A pair of Swordtail fish courtesy of Molly Cummings |
Nature provides a curious conundrum for male animals. On one hand, they want to attract a mate. So animals will need bright colours, or a loud voice to make them obvious to females. But at the same time, they don't want to advertise their presence to predators, since this will mean they'll end up as somebody's lunch.
The Mexican swordtail fish has come up with one solution to this problem. The males of one species have a bright tail that can only be seen by the females. Predators can't see it. The trick is to have a tail that's only reflective under ultraviolet light-a part of the spectrum that's invisible to their predators. Dr. Molly Cummings is an evolutionary biologist at the University of Texas and part of the team that discovered the secret signal.
Related Links
Lucky Seven
Listen to an mp3 of this topic or download the Ogg file. (what's
ogg?)
The draft sequence of the human genome was published about two years ago. But that map was only a rough outline of all our genes. This week, in the journal Science, a group led by Canadian scientists published a much more detailed map of one section of the genome.
They describe all the genes on Chromosome seven. Dr. Steve Scherer is a scientist at the Hospital for Sick Children in Toronto. He led the team that sequenced chromosome seven.
Related Links
[last week] [next week]
|
|
