There's no single, universally agreed upon point where outer space begins. It's more of a gradual transition.

Here are some key points to consider:

* The Kármán Line: This is the most widely accepted definition. It's at 100 kilometers (62 miles) above sea level. It's where the atmosphere becomes too thin to support aeronautical flight.

* The Thermosphere: This layer of the atmosphere starts around 80 kilometers (50 miles) above sea level and extends to around 600 kilometers (375 miles). It's characterized by very thin air and increasing temperatures.

* The Exosphere: This is the outermost layer of the atmosphere. It extends to about 10,000 kilometers (6,200 miles) and gradually fades into the vacuum of space.

So, while the Kármán Line is the most accepted answer, it's important to remember that the transition from Earth's atmosphere to outer space is a gradual one.