Answer:
Radio telescopes, telescopes detecting infrared radiation, gamma rays, and X-rays and space-based telescopes are essential in modern astronomy.
Answer:
4 billion years
Explanation:
Scientists have found the oldest known rocks on Earth. They are 4.28 billion years old, making them 250 million years more ancient than any previously discovered rocks. Earth formed about 4.6 billion years ago from a disk of gas and dust circling the sun.
The world's tallest artificial structure is the 829.8-meter-tall (2,722 ft) Burj Khalifa<span> in Dubai. The building gained the official title of "Tallest Building in the World" and the tallest self-supported structure at its opening on January 9, 2010.</span>
