1) The Earth's core is primarily composed of iron and nickel and is as hot as the surface of the sun.

2) The Internet of Things (IoT) refers to the network of physical devices, vehicles, appliances, and other objects embedded with sensors, software, and connectivity.

3) The concept of self-driving cars, or autonomous vehicles, is being actively developed by companies such as Tesla, Google (Waymo), and Uber.

4) Hugh Jackman is an Australian actor, singer, and producer best known for his portrayal of Wolverine in the "X-Men" film series. He has also starred in musicals such as "Les Misérables" and "The Greatest Showman" and has received critical acclaim for his performances.