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Should We Use Comets and Asteroids to Terraform Mars?
First, I would like to thank all those who watched the Sci Fi Science debut and made it such a smashing success. I was overwhelmed by all the response. I did a web chat last week, and so many people logged on that the server crashed, so I would also like to apologize to those who might have been inconvenienced that day.
Second, I would like to comment about some of the questions that came pouring in after that episode. I certainly can't possibly answer all the questions, but here are a few responses that I have chosen.
Question One: If you terraform Mars, making it into a Garden of Eden, won't this be temporary, since Mars isn't big enough to permanently hold onto an atmosphere.
Answer: You are absolutely correct. Mars is a small planet, and hence it's gravitational field is not strong enough to permanently hold onto a dense atmosphere, but it is sufficient to hold onto an atmosphere for thousands to millions of years, which is enough for us. Once we terraform Mars, there will be enough of an atmosphere to take of all our needs for generations to come.
But it does mean that future generations, thousands of years from now, will have to replenish the atmosphere once again. For our purposes, however, it does not matter.
Question Two: Won't sending comets and asteroids down on Mars cause lots of destruction to the surface?
Answer: In the program, we mentioned that it might be possible to heat up Mars using nuclear power plants, but this would be a very slow, expensive, and perhaps dangerous plan. A much faster plan would be to divert comets and meteors to Mars. We also mentioned that, if you aim the comet or meteor carefully, you can control its orbit. This means you can gently have the comet or meteor enter Mars orbit, and then slowly descend to the surface as the orbit decays. This means that much of the comet or meteor will burn up in the atmosphere and release water vapor. The point here is that we can accurately aim the comet or meteor so that we can minimize surface damage but maximize energy transfer, which is what we need to heat up Mars.
Question Three: What is the time frame for terraforming Mars?
Answer: Not anytime soon. A good guess is that we will have our astronauts on Mars by mid-century (given the set-backs in the current manned missions to space). So the first colonies will be established by later in the 21st century. Terraforming won't begin until many decades after that. So we are talking about mid 22nd century before terraforming can be considered seriously. But as Carl Sagan was fond of pointing out, we should become a two planet species, since it is simply too dangerous to place the future of humanity on just one planet.
Next: How to Deflect Meteors and Comets
A Mercury-bound spacecraft's noisy flyby of our home planet.
- There is no sound in space, but if there was, this is what it might sound like passing by Earth.
- A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
- Yes, in space no one can hear you scream, but this is still some chill stuff.
First off, let's be clear what we mean by "hear" here. (Here, here!)
Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.
All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.
Image source: European Space Agency
The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.
Into and out of Earth's shadow
In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.
The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."
In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."
When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.
The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.
BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.
MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.
Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.
Erin Meyer explains the keeper test and how it can make or break a team.
- There are numerous strategies for building and maintaining a high-performing team, but unfortunately they are not plug-and-play. What works for some companies will not necessarily work for others. Erin Meyer, co-author of No Rules Rules: Netflix and the Culture of Reinvention, shares one alternative employed by one of the largest tech and media services companies in the world.
- Instead of the 'Rank and Yank' method once used by GE, Meyer explains how Netflix managers use the 'keeper test' to determine if employees are crucial pieces of the larger team and are worth fighting to keep.
- "An individual performance problem is a systemic problem that impacts the entire team," she says. This is a valuable lesson that could determine whether the team fails or whether an organization advances to the next level.