Extras

    Video thumbnail: Science Trek Gravity: Is gravity less where you live?

    Science Trek

    Gravity: Is gravity less where you live?

    Gravity isn't the same everywhere on Earth.

    Gravity: Is gravity less where you live?

    Video thumbnail: Science Trek Gravity: What is a Black Hole?

    Science Trek

    Gravity: What is a Black Hole?

    How do they see black holes?

    Gravity: What is a Black Hole?