Threats from Space

Launched by the Soviet Union, The Sputnik 1 was the first artificial satellite created by humankind. This satellite initiated the space race between the Soviets and the United States, ultimately leading the United States to establish NASA (National Aeronautics and Space Administration) the following year.¹

Yuri Gagarin: The Soviet cosmonaut Yuri Gagarin became the first ever human to venture into space and return safely on April 12, 1961. In addition to Sputnik, this accomplishment increased the competition in the Space Race between the US and the Soviets.

Moon landing: The American astronauts Neil Armstrong and Buzz Aldrin became the first humans to set foot on an extraterrestrial object in space on July 20th, 1969. They fulfilled President John. F. Kennedy’s wish of having a man on the moon at the end of the decade and made international history. Armstrong’s famous quote “That’s one small step for man, one giant leap for mankind” originated then, as hundreds of millions of people witnessed one of America’s proudest moments on their televisions. The two astronauts spent two and a half hours on the surface collecting rocks, soil samples, and using lasers to measure the distance between the moon and the Earth.

Launch of Voyagers: Voyagers 1 and 2 were launched in 1977 to take pictures of Jupiter and Saturn, discovering active volcanoes on Jupiter’s moon and the composition and nature of Saturn’s rings. After passing these planets, they continued to travel away from Earth in different directions, reaching interstellar space in 2012 (Voyager 1) and 2018 (Voyager 2).

Hubble Space Telescope: The Hubble Space Telescope, launched by NASA and the European Space Agency in 1990, became the first large telescope to be placed in space and orbit the Earth. It was named after the astronomer Edwin Powell Hubble and placed into orbit by the space shuttle Discovery. Due to its placement above the clouds, the telescope can capture high-resolution imagery of space, enabling NASA to make technological advancements.

International Space Station: The ISS (International Space Station) was launched in 1998 and is a multinational habitable artificial satellite, located in Earth’s lower orbit. It can be seen by the naked eye and is the largest artificial satellite located in space. Fifteen different nations manage the ISS, but the main contributors are NASA (United States), Roscosmos (Russia), and the European Space Agency. The ISS serves as a platform to research the long-term effects of space on human health providing key insights for potential habitats on other solar system destinations like the moon or Mars.

Threats

Since the existence of the first living organism on Earth three and a half billion years ago, at least five mass extinctions have occurred, destroying most of the species occupying our planet. Although society has rapidly progressed in the past few millennia, Earth continues to face existential threats from outer space.

Causes

Asteroid Impacts – Rocky bodies orbiting the sun that could make a direct trajectory towards Earth (odds of this happening are exceptionally low).

Gamma Ray Bursts – The most powerful and luminous explosions observed in the universe (produced during the formation of black holes).²

Solar flares – Powerful explosions of energy released by the sun caused by the tangling of magnetic field lines in sunspots. They emit clouds of plasma into space known as Coronal Mass Ejections (CMEs) that can hit the Earth.³

Sun transforming into a red giant – In around 5.4 billion years, the Sun will transition from a main sequence star into its next stage in the solar cycle: the red giant phase. All the hydrogen contained in the sun’s core will be exhausted by this time, and the sun will begin burning helium. This will make the core denser and cause the atmosphere to enlarge, engulfing Mercury, Venus, and possibly the Earth.

Effects

Asteroid Impacts – The effects of asteroids depend on the size. For instance, an asteroid with a 10 km diameter would cause a global impact for about 100 million years. This would lead to mass extinctions, ozone destruction, heating of the atmosphere by greenhouse gases, global acid rain, and severe natural disasters. Smaller asteroids would have similar effects but on a smaller scale.⁴

Gamma Ray Bursts – The effects of gamma ray bursts on Earth in the past help scientists predict potential future scenarios. Gamma radiation resulting from a burst would destroy Earth’s protective ozone layer, allowing harmful UVB radiation to reach Earth’s surface. Additionally, these bursts would destabilize the oxygen molecules in the air, producing harmful ozone in the lower layers of the atmosphere. Ground level damages plant cells by reducing chlorophyll production and even destroying them.⁵

Solar flares – Coronal Mass Ejections resulting from solar flares can produce geomagnetic storms that can cause power outages and damaged satellites for communication. Such damage poses a risk to astronauts or aircraft passengers in the upper atmosphere.⁶ Although solar flares cannot directly lead to mass extinction, the impact of a G5 solar storm (most powerful classification) includes widespread voltage control problems, the destruction of power grids, disruption in satellite communication systems, and the loss of billions of dollars.⁷

Sun transforming into a red giant – With the sun’s expansion into a red giant, the Earth is predicted to be completely engulfed by the sun’s atmosphere, destroying the planet and its ability to house forms of life.⁸ In roughly a billion years, the sun’s brightness will increase by about 10%, shifting the location of the solar system’s habitable zone (the area around a star in which liquid water can exist on the surface of planets) and placing Earth outside of it. Without liquid water, the Earth would be unable to sustain human life, forcing humanity to find a habitable exoplanet to migrate to within the next billion years.⁹

Solutions

Some practical solutions for humanity if the Earth encounters any of these existential threats include:

· Space colonization – The settlement of humanity on planets other than the Earth. Although it will require vast technological advancements, space colonies would enable humanity to continue on a new planet, make new scientific discoveries, and experience life in a different solar system. Viable options for future colonization include Mars (due to studies showing that water existed on the planet in the past), Titan (it has frozen water, liquid hydrocarbons, and an atmosphere),¹⁰ and other habitable exoplanets including Teegarden’s Star b (12 light years away), TOI-700 d (102 light years away), and many other earthlike planets that are theorized to support life.¹¹

· Destruction of an asteroid through human methods – Simulations at the NASA Jet Propulsion Laboratory have shown that firing a nuclear warhead at an asteroid could prevent 99% of it from colliding with Earth’s surface. However, such an operation would require immense power – approximately 50 times stronger than the atomic bomb that destroyed Hiroshima. The larger the asteroid, the sooner the nuke would need to be fired to prevent extensive damage to Earth. Additionally, there is a possibility of multiple fragments causing more damage to Earth than a single asteroid would, so this method is only to be used as a last-minute resort.¹²

References

¹History.com (2021) “Sputnik launched” History.com, https://www.history.com/this-day-in-history/sputnik-launched

²Mann, Adam. ”What is a Gamma-Ray Burst?” Space.com, 5 Jan. 2020, https://www.space.com/gamma-ray-burst.html

³Smith, Adam.” Solar flares: what are they, what causes them, and how dangerous are they to humans?” Independent, 26 May 2021, https://www.independent.co.uk/tech/solar-flares-sun-geomagnetic-storm-earth-b1854385.html

⁴Paine, Michael.” Environmental Damage from Asteroid and Comet Impacts.” The Planetary Society, 27 May 2004, http://www.vdrsyd.com/planet/climate.htm

⁵Gronstal, Aaron. ”How Deadly Would a Nearby Gamma Ray Burst Be?” NASA, https://astrobiology.nasa.gov/news/how-deadly-would-a-nearby-gamma-ray-burst-be/

⁶Lynch, Benjamin. ”What would happen if a huge solar flare hit Earth? Including Northern Lights in Africa” Mirror, 19 Oct 2021, https://www.mirror.co.uk/science/what-would-happen-huge-solar-25247961

⁷Morales, Marie.”Solar Storm Radiation Risk May Occur As Strongest ‘G5’ Category Happens Resulting to Major Sun Plasma Eruption.” The Science Times, 11 Apr. 2022, https://www.sciencetimes.com/articles/37114/20220411/solar-storm-radiation-risk-occur-strongest-g5-category-happens-resulting.htm

⁸” What will happen to the planets when the Sun becomes a red giant?” Astronomy.com, 18 Sep. 2020, https://astronomy.com/magazine/ask-astro/2020/09/what-will-happen-to-the-planets-when-the-sun-becomes-a-red-giant

⁹” The sun won’t die for 5 billion years, so why do humans have only 1 billion years left on Earth?” The Conversation, 12 Feb. 2015, https://theconversation.com/the-sun-wont-die-for-5-billion-years-so-why-do-humans-have-only-1-billion-years-left-on-earth-37379

¹⁰Alexander, Donovan. ”Beyond Mars, Other Places in Our Solar System We Could Colonize.” Interesting Engineering, 10 Jul. 2020, https://interestingengineering.com/beyond-mars-other-places-in-our-solar-system-we-could-colonize

¹¹”The Habitable Exoplanets Catalog.” PHL, 6 Dec. 2021, https://phl.upr.edu/projects/habitable-exoplanets-catalog

¹²Morrison, Ryan. ”Nuking an incoming asteroid COULD actually work.” DailyMail, 15 Oct. 21, https://www.dailymail.co.uk/sciencetech/article-10095597/Nuking-incoming-asteroid-actually-work-study-shows.html