Razor Thin: A New Perspective on Earth’s Atmosphere

Earth is the only known planet that sustains life. Its atmosphere provides us with oxygen, protects us from the Sun’s radiation, and creates the barometric pressure needed so water stays liquid on our planet.

But while Earth’s atmosphere stretches for about 10,000 km (6,200 miles) above the planet’s surface, only a thin layer is actually habitable.

This graphic, inspired by Andrew Winter, shows just how small Earth’s “habitable zone” is, using the state of Florida as a point of reference.

Earth’s Like an Onion: It Has Layers

Our planet’s atmosphere is made up of a unique cocktail of gases—roughly 78% nitrogen and 21% oxygen, with trace amounts of water, argon, carbon dioxide, and other gases.

It’s separated into five different layers:

• Exosphere: The uppermost layer of our atmosphere that melds into outer space.
• Thermosphere: Begins at around 80 km (50 miles) above sea level and extends to approximately 600 km (372 miles), reaching temperatures as high as 2,000°C (3,600°F).
• Mesosphere: Around 30 km (19 miles) in range, meteors burn as they pass through this layer, creating “shooting stars.”
• Stratosphere: Home to the ozone layer, which is responsible for absorbing a majority of the sun’s radiation.
• Troposphere: The closest layer to ground. It stretches about 7–15 kilometers (5–10 miles) from the surface.

The troposphere makes up approximately 75-80% of the atmosphere’s mass, as it’s where most of the dust, ash, and water vapor are stored. But only a part of this layer is suitable for human life—in fact, the atmosphere’s habitable zone is so small, several mountain ranges extend beyond it.

Reaching Into Earth’s Atmosphere: Extremely High Altitudes

Elevations above 5,500 meters (18,000 ft) are considered extremely high altitude and require special equipment and/or acclimatization in order to survive. Even then, those who choose to venture to extreme heights run the risk of getting altitude sickness.

When it comes to the world’s tallest mountain ranges, the Himalayas are the highest. At their peak, Mount Everest, the Himalayas reach 8,848 m (29,000 ft) above sea level.

Despite the dangers of extreme altitude, hundreds of mountaineers attempt to climb Mount Everest each year. On Everest, the region above 8,000 m (26,000 feet) is referred to as the “death zone,” and climbers have to bring bottled oxygen on their trek in order to survive.

Life Beyond Earth

Earth is the only known planet with an atmosphere we can survive in. And even on Earth, certain areas are considered dead zones.

But there may be other life forms out in the galaxy that we haven’t discovered. Recent research in The Astrophysical Journal predicts there are at least 36 intelligent civilizations throughout the galaxy today.

So life may very well exist beyond Earth. It just might look a bit different than we’re used to.

The Size of The World’s Rockets, Past and Present

The SpaceX Starship might be the next rocket to take humans to the moon, but it won’t be the first, and likely not the last.

Starting in the mid-20th century, humanity has explored space faster than ever before. We’ve launched satellites, telescopes, space stations, and spacecrafts, all strapped to rocket-propelled launch vehicles that helped them breach our atmosphere.

This infographic from designer Tyler Skarbek stacks up the many different rockets of the world side-by-side, showing which country designed them, what years they were used, and what they (could) accomplish.

How Do The World’s Rockets Stack Up?

Before they were used for space travel, rockets were produced and developed to be used as ballistic missiles.

The first rocket to officially reach space—defined by the Fédération Aéronautique Internationale as crossing the Kármán line at 100 kilometers (62 miles) above Earth’s mean sea level—was the German-produced V-2 rocket in 1944.

But after World War II, V-2 production fell into the hands of the U.S., the Soviet Union (USSR), and the UK.

Over the next few decades and the unfolding of the Cold War, what started as a nuclear arms race of superior ballistic missiles turned into the Space Race. Both the U.S. and the USSR tried to be the first to achieve and master spaceflight, driving production of many new and different rockets.

As the Space Race wound down, the U.S. proved to be the biggest producer of different rockets. The eventual dissolution of the USSR in 1991 transferred production of Soviet rockets to Russia or Ukraine. Then later, both Europe (through the European Space Agency) and Japan ramped up rocket production as well.

More recently, new countries have since joined the race, including China, Iran, and India. Though the above infographic shows many different families of rockets, it doesn’t include all, including China’s Kuaizhou rocket and Iran’s Zuljanah and Qased rockets.

Rocket Range Explained and Continued Space Aspirations

Designing a rocket that can reach far into space while carrying a heavy payload—the objects or entities being carried by a vehicle—is extremely difficult and precise. It’s not called rocket science for nothing.

When rockets are designed, they are are created with one specific range in mind that takes into account the fuel needed to travel and velocity achievable. Alternatively, they have different payload ratings depending on what’s achievable and reliable based on the target range.

• Suborbital: Reaches outer space, but its trajectory intersects the atmosphere and comes back down. It won’t be able to complete an orbital revolution or reach escape velocity.
• LEO (Low Earth orbit): Reaches altitude of up to ~2,000 km (1242.74 miles) and orbits the Earth at an orbital period of 128 minutes or less (or 11.25 orbits per day).
• SSO (Sun-synchronous orbit): Reaches around 600–800 km above Earth in altitude but orbits at an inclination of ~98°, or nearly from pole to pole, in order to keep consistent solar time.
• GTO (Geosynchronous transfer orbit): Launches into a highly elliptical orbit which gets as close in altitude as LEO and as far away as 35,786 km (22,236 miles) above sea level.
• TLI (Trans-lunar injection): Launches on a trajectory (or accelerates from Earth orbit) to reach the Moon, an average distance of 384,400 km (238,900 miles) from Earth.

But there are other ranges and orbits in the eyes of potential spacefarers. Mars for example, a lofty target in the eyes of SpaceX and billionaire founder Elon Musk, is between about 54 and 103 million km (34 and 64 million miles) from Earth at its closest approach.

With space exploration becoming more common, and lucrative enough to warrant billion-dollar lawsuits over contract awards, how far will future rockets go?