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Explainer: Where exactly does space begin?

Jeff Bezos set off in a rocket today – but did he actually go to space?

Image: ABACA

EARLIER TODAY, THE wealthiest man on the planet Jeff Bezos flew to and from the edge of space in his own rocket. 

Bezos’ company Blue Origin flew a rocket just above the Karman line – a commonly referenced definition for the boundary between Earth and space.

Earlier this month, billionaire Richard Branson also flew to the edge of space – but his rocket strayed just below this line.

However, there is no set limit for the edge of space and experts differ on where the boundary is established.

What do most experts say about the edge of space?

There is no universal acceptance for where space begins but the World Air Sports Federation (FAI) uses the Karman line, which sets the boundary at 100km/62 miles above sea level.  

The FAI stewards definitions for spaceflight. However, the 100km figure is debated and many experts believe the boundary is closer than this. 

David Moore of Astronomy Ireland said the work of US astronomer Jonathan McDowell and others indicate that the limit “probably is closer to 80km” above sea level. 

He said people are weightless at 80-90km above sea level, the sky is fully black and you can see the curvature of the Earth. 

“In the aerospace industry it has always been a topic of conversation because Nasa and the US military were always awarding their people astronaut wings when they got above 80km,” Moore told The Journal.  

However, he said it “wasn’t really a big issue” in the past because humans were generally going further into the depths of space.

blue-origin-bezos Blue Origin's New Shepard rocket launching today. Source: Tony Gutierrez

The International Space Station, for example, is 400km above the Earth’s surface (for avid sky-watchers, Moore said the ISS is visible over Irish skies at night this week).

“It’s only when space tourist companies like Virgin Galactic and a few others [facilitate] people going up just as far as they need to get astronaut wings,” Moore said.

He believes the debate around the exact edge of space will become “a lot more important in the future” as space tourism grows.

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pictures-of-the-week-north-america-photo-gallery Virgin Galactic founder Richard Branson carries crew member Sirisha Bandla on his shoulders after they returned to Earth. Source: Andres Leighton

How far up did Bezos and Branson go?

Virgin Galactic founder Richard Branson took a trip to the edge of space on 11 July.

Branson’s space flight reached around 88km/55 miles above the Earth’s surface. Bezos today travelled around 106km/66 miles. 

This fuelled discussions of whether Branson technically travelled to space as his flight fell under the Karman line. 

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