The Key to Finding Life Elsewhere in the Universe: Purple Planets?!?

The video explores the color of exoplanet HD 189733B and Earth's historical color changes. It discusses chlorophyll's role in photosynthesis and its inefficiency in absorbing green light. The video introduces the hypothesis that Earth might have been dominated by purple, retinal-using organisms before chlorophyll became prevalent. This idea is significant for astronomers searching for extraterrestrial life, as a purple planet could exist. The video also highlights the potential of future telescopes like HabEx to detect such planets.

What color might Earth have been 3.5 billion years ago according to some scientists?

• Green

• Blue

• Purple

• Red

What pigment do some organisms use instead of chlorophyll to capture light energy?

• Xanthophyll

• Carotene

• Retinal

• Anthocyanin

Why might retinal-based organisms have evolved before chlorophyll-based ones?

• Retinal-based processes are simpler

• Retinal is more complex to produce

• Retinal absorbs less abundant light

• Retinal requires more energy to function

What advantage does chlorophyll have over retinal in terms of energy efficiency?

• Chlorophyll can produce oxygen

• Chlorophyll reflects more light

• Chlorophyll is easier to produce

• Chlorophyll absorbs more green light

What is the significance of the oxygen produced by chlorophyll-based organisms?

• It caused the extinction of retinal-based organisms

• It reduced the amount of sunlight reaching Earth

• It made Earth less habitable

• It led to the evolution of more complex life

What might astronomers look for when searching for signs of extraterrestrial life on a purple planet?

• A green edge in the light spectrum

• A blue edge in the light spectrum

• A yellow edge in the light spectrum

• A red edge in the light spectrum

What future technology could help us find evidence of a purple planet?

• Habitable Exoplanet Observatory

• Kepler Space Telescope

• Hubble Space Telescope

• James Webb Space Telescope