Final answer:
Actually, all the options listed are considered possible explanations for dark matter. These include it being composed of dense objects like black holes, being very cold, being made of subatomic particles like neutrinos, or being a completely new form of matter.
Step-by-step explanation:
The question asks which of the following is NOT a possible explanation of dark matter:
- Dark matter is composed of very dense, invisible objects like black holes
- Dark matter is so cold that it does not shine bright enough for us to see it
- Dark matter is composed of strange subatomic particles like neutrinos
- Dark matter is composed of a whole new type of matter unlike anything we have ever seen on earth
All these options are, in fact, considered possible explanations for dark matter. Current research suggests dark matter could be something we haven't detected on Earth yet and experiments are underway to discover its composition. It may comprise exotic subatomic particles that are not part of our current understanding of matter, or it could be made of normal particles like protons and neutrons found in objects like black holes, brown dwarfs, or white dwarfs, which would be difficult to detect. Dark matter might also be cold and interact weakly with ordinary matter, which would explain why it's invisible to us.