To help develop lessons around the content in Extrasolar, we're providing a few questions to help get discussion started on various topics. You can find more on our lesson plans page.
Q (Astronomy): If you look closely at your night photos, you may recognize some familiar constellations that look almost identical to the constellations that you would see here on earth. That may seem surprising since the planet that you're exploring orbits a star -- Epsilon Eridani -- that is nearly 10.5 light years (100 trillion kilometers) away. Why would the night sky look so similar to ours?
A: 10.5 light years may seem like a huge distance -- and it is -- but relative to the size of the milky way galaxy, it's hardly any distance at all. The Milky Way is more than 100,000 light years across. By comparison, the closest star to Earth -- Proxima Centauri -- is 4.2 light years away. If you were to travel 10.5 light years, only a few stars would appear to noticeably change their position.
Q (Biology): Almost none of the species on Epsilon Eridani e are green in color. Why is this surprising and what might be your hypothesis about how species get energy for life?
A: On Earth, chlorophyll a is one of the principle molecules used for photosynthesis. It reflects a green color, giving plants their characteristic green look. Since we don't see green on Epsilon Eridani e, we can hypothesize that the species get their energy from somewhere else -- it could be a different molecule that they use for photosynthesis, or it might be that they get their energy from some other source entirely.
Q (Biology): In one of your first missions, the team biologist Jane Eastwood explains you that it would be incorrect to refer to any of the species that you see on Epsilon Eridani e as "plants" and encourages you to instead use a term that she makes up -- "photobionts". They look like plants, so why isn't it scientifically correct to call them plants?
A: Species in the plant kingdom on Earth are all related to a common evolutionary ancestor. Since the species on Epsilon Eridani e have evolved independently, they don't share any of the ancestors of the plant kingdom.
Q (Biology): If the species on Epsilon Eridani e evolved independently from species on Earth, then why do some of the photobionts look so similar to Earth plants?
A: The evolutionary pressures on Epsilon Eridani e are similar to those on Earth. Species need to harness energy, replicate, conserve resources, and defend against predators. The result is that species on both planets may evolve similar structures. This is known as convergent evolution.
Q (Physics): In Extrasolar, it takes a minimum of one hour for you to send a command to your rover, wait for your rover to travel to its new location, and send a photo back to Earth. Would this speed of communication be possible in real life?
A: If data is transmitted with electromagnetic waves, then our communications are bounded by the speed of light. Even within our own solar system, this can cause long delays. Depending on where Earth and Mars are in their orbits, it can take 5-20 minutes for light to go between them (meaning a round-trip signal time of 10-40 minutes) Since Epsilon Eridani e is 10.5 light years away, a round-trip message would take 21 years!