avatar - Why is Pandora's atmosphere so toxic to humans, yet still so conducive to life?

I wasn't able to put my finger on it. Avatar wiki says:

Pandora's toxic atmosphere is unbreathable by humans due to the presence of high concentrations of carbon dioxide (>18%) and hydrogen sulfide (>1%).

However, entire planet seemed to be covered in plants, including water plants. Earth isn't half as green as Pandora is, but it still has pretty low levels of carbon dioxide (0.035%) even with all the emissions that come from human society.

I understand about the air toxicity due to other chemicals found in the atmosphere, but if the plants are performing photosynthesis, shouldn't it be enough to keep the atmosphere relatively free of carbon dioxide?

Answer

Alien planet, alien plants. Just because they appear to be similar to Earth plants doesn't mean they necessarily behave identically to Earth plants. It would be entirely possible for an alien plant to do the opposite of our plants: take in oxygen and expel carbon dioxide. The plants on Pandora are specially suited to that planet's ecosystem, so while they may perform something like photosynthesis they likely absorb and expel different types of chemicals and in different amounts than Earth plants.

Comments

harry potter - Do the Kwikspell courses work?

In Harry Potter we are introduced to Kwikspell course in The Chamber of Secrets (and never hear about it again). We see Filch taking courses, presumably by mail. The descriptions of Kwikspell make me think it is for people who are weak in magic (kind of like how Neville was supposed to be when he was younger), but had magic in them nonetheless. However, Ron's comments later in the chapter make it sound like it is mainly for Squibs to learn magic. However, it is strongly implied through out all the books that Squibs are essentially Muggles, and will never be able to do magic. How then is a Kwikspell course supposed to work? Do we have any information to know if it works at all? Is it a scam? An answer from any level of canon is welcome. Answer Kwikspell courses are (probably) useful to some wizards, but not to squibs. The Kwikspell course literature comes with two testimonials. Madam Z. Nettles of Topsham writes: ‘I had no memory for incantations and my potions were a family joke...

futurama - How much time is lost in 'Time Keeps on Slippin''

In time Keeps on Slippin' , Farnsworth creates a basketball team which he matures by abusing Chronitons. This leads to time skipping forward by random, but ever increasing amounts. How much time was skipped in this way? Answer Unfortunately, I don't think a good estimate can be made for this, for two reasons: Many of the time skips move forward by an indeterminate amount of time. At one point, the Professor mentions localized regions of space skipping forward much more than others. We then see two young boys on the street below complaining about having to pay social security, only to suddenly become senior citizens and start complaining about wanting their money. Thus, each individual could have experienced a different amount of time skippage.

star trek - Warning regarding forward saucer section in Nemesis?

In Star Trek: Nemesis , just before the Enterprise rams into the Scimitar, Picard sends a text message from his captain's chair arm pad to Troi — who is manning the helm in lieu of the crewman who was just blown out through what was once the view screen — indicating that she should put full impulse on standby. (Literally, if you watch the scene closely, Troi's console prefaces the order with "TXT MSG" !) My question is: Did Picard also somehow warn crew members in the forward saucer section about what was about to happen? The ramming of the Scimitar was a heat of the moment decision. Considering that he also resorted to calling the auto-destruct sequence shortly after (which ended up being offline), he probably was of the mindset that any losses would be acceptable in order to hault Shinzon's march to Earth. Still, I'm curious. Answer The original script indicates that he called for the crew to " brace for impact ". Whether that call (or the comma...

star wars - What "exactly" happens when someone turns to the Dark Side?

When I saw the original Star Wars saga as a kid, the concept of the Dark Side imprinted in me was quite simple. You did a bad thing, so you're a bad person so you go to the Dark Side and keep doing bad things. Now, obviously this doesn't hold true in reality. In my mind it is perfectly reasonable for Luke to kill the Emperor and Vader and then just flee the Death Star and rejoin the Alliance. After all they are at war, those are enemy officers that have captured him and are taunting him by threatening with death of all loved ones and the whole operation was intended to kill the Emperor anyway. The same would hold true for Anakin. He could have killed Mace Windu to save the Chancellor and Padme but that doesn't mean he's going to then go mad and kill all Jedis including children. It doesn't add up from a merely psychological point of view. He had a set of objectives and that made him want to keep the Chancellor alive (quite valid by the way, Mace Windu is quite clums...

Blog

Search This Blog