7. Which is a characteristic of dark matter?
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1 point
it does not interact with baryonic matter
it has not been observed directly.
it interacts with electromagnetic radiation.
humans can see it
The correct answer is: it does not interact with baryonic matter. Dark matter is a hypothetical form of matter that does not interact with or emit electromagnetic radiation, which is why it cannot be directly observed.
The characteristic of dark matter is that it does not interact with baryonic matter.
The correct answer is: it does not interact with baryonic matter.
To arrive at this answer, one can use the process of elimination. Let's go through each option:
1. it does not interact with baryonic matter: This is a characteristic of dark matter. Dark matter does not interact with baryonic matter, which is the type of matter that makes up the visible universe, including stars, planets, and people.
2. it has not been observed directly: While it is true that dark matter has not been observed directly, this is not a defining characteristic of dark matter. There are indirect observations and evidence that suggest the presence of dark matter in the universe.
3. it interacts with electromagnetic radiation: Dark matter neither emits nor absorbs electromagnetic radiation, which is another way of saying that it does not interact with electromagnetic radiation. This is a characteristic of dark matter, but it is not the main characteristic that distinguishes it.
4. humans can see it: Dark matter is called "dark" precisely because humans cannot see it with our current understanding of the electromagnetic spectrum. Dark matter does not emit, reflect, or absorb light, making it invisible to human observation.
By process of elimination, we can conclude that the correct characteristic of dark matter is that it does not interact with baryonic matter.
8. Which statement is INCORRECT about Cosmic Microwave Background radiation?
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2 points
its temperature is uniform.
it consists of electromagnetic radiation that is a remnant of the Big Bang.
It appears uniformly across the universe.
it appeared only a few years ago
The incorrect statement about Cosmic Microwave Background radiation is: it appeared only a few years ago.
The Cosmic Microwave Background radiation is a remnant of the Big Bang and has been present since the early stages of the universe's formation. It permeates the entire observable universe and appears uniformly, providing evidence for the Big Bang theory. The temperature of the Cosmic Microwave Background radiation is also observed to be nearly uniform across the sky.