
A Speakers' Corner is an area where open-air public speaking, debate, and discussion are allowed. The original and most noted is in the north-east corner of Hyde Park in London, England. Speakers here may talk on any subject, as long as the police consider their speeches lawful, although this right is not restricted to Speakers' Corner only. Contrary to popular belief, there is no immunity from the law, nor are any subjects proscribed, but in practice the police intervene only when they receive a complaint. Speakers' Corner is often held up to demonstrate freedom of speech, as anyone can turn up unannounced and talk on almost any subject, although always at the risk of being heckled by regulars.

The Universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy. While the spatial size of the entire Universe is still unknown, it is possible to measure the observable universe. The earliest scientific models of the Universe were developed by ancient Greek and Indian philosophers and were geocentric, placing Earth at the centre of the Universe. Over the centuries, more precise astronomical observations led Nicolaus Copernicus to develop the heliocentric model with the Sun at the centre of the Solar System.