In 2019 we caught our first plastic. However, the catch amount was low, and our calculations showed it would take too long to clean up the GPGP using that original design. We decided to move to an active cleanup approach, and after some prototyping and field testing, we received proof of technology in 2021. This meant we had successfully met the following criteria: limited negative environmental impact, no safety issues during operation, and of course, repeatedly harvesting large amounts of plastic. Taking on such an ambitious challenge and solving problems nobody has ever solved before requires a fast and iterative approach – so we keep learning and improving every day.
Cleaning up the garbage patches
Ocean plastic accumulates in five ocean garbage patches, the largest one being the Great Pacific Garbage Patch, located between Hawaii and California. To solve it, we not only need to stop more plastic from flowing into the ocean, but also clean up what is already out there. Floating plastics trapped in the patches will keep circulating until they break down into smaller and smaller pieces, becoming harder to clean up and increasingly easier to mistake for food by sealife. If left to circulate, the plastic will impact our ecosystems, health, and economies for decades or even centuries.
Illustration of ocean gyres
Cleaning the ocean garbage patches
The fundamental challenge of cleaning up the ocean garbage patches is that the plastic pollution is highly diluted, spanning millions of square kilometers. Our cleanup solution is designed to first concentrate the plastic, allowing us to effectively collect and remove vast quantities. This is how it works:
To clean an area of this size, a strategic and energy-efficient solution is required. With a relative speed difference maintained between the cleanup system and the plastic, we create artificial coastlines, where there are none, to concentrate the plastic. The system is comprised of a long U-shaped barrier that guides the plastic into a retention zone at its far end. Through active propulsion, we maintain a slow forward speed with the system.
SCALING UP
We captured our first plastic from the GPGP in 2019 and in 2021 we reached proven technology. Today, our total catch runs to hundreds of tons and counting, and as we continuously improve our operations, our catches become larger and more reliable. In 2022, we began transitioning to the three-times larger System 03 by upgrading and replacing components gradually while continuing to harvest plastic. In August 2023, System 03 was deployed to the GPGP for the first time. Cleaning the entire GPGP requires a fleet of cleaning systems, and we believe that System 03 will allow us to develop our blueprint for that scale-up, all while continuing to extract unprecedented amounts of plastic.
The Electromagnetic Spectrum
The electromagnetic (EM) spectrum is the range of all types of EM radiation. Radiation is energy that travels and spreads out as it goes the visible light that comes from a lamp in your house and the radio waves that come from a radio station are two types of electromagnetic radiation. The other types of EM radiation that make up the electromagnetic spectrum are microwaves, infrared light, ultraviolet light, X-rays and gamma-rays.
You know more about the electromagnetic spectrum than you may think. The image below shows where you might encounter each portion of the EM spectrum in your day-to-day life.
The electromagnetic spectrum from lowest energy/longest wavelength (at the top) to highest energy/shortest wavelength (at the bottom). (Credit: NASA’s Imagine the Universe)
Radio: Your radio captures radio waves emitted by radio stations, bringing your favorite tunes. Radio waves are also emitted by stars and gases in space.
Microwave: Microwave radiation will cook your popcorn in just a few minutes, but is also used by astronomers to learn about the structure of nearby galaxies.
Infrared: Night vision goggles pick up the infrared light emitted by our skin and objects with heat. In space, infrared light helps us map the dust between stars.
Visible: Our eyes detect visible light. Fireflies, light bulbs, and stars all emit visible light.
Ultraviolet: Ultraviolet radiation is emitted by the Sun and are the reason skin tans and burns. “Hot” objects in space emit UV radiation as well.
X-ray: A dentist uses X-rays to image your teeth, and airport security uses them to see through your bag. Hot gases in the Universe also emit X-rays.
Gamma ray: Doctors use gamma-ray imaging to see inside your body. The biggest gamma-ray generator of all is the Universe.
Is a radio wave the same as a gamma ray?
Are radio waves completely different physical objects than gamma-rays? They are produced in different processes and are detected in different ways, but they are not fundamentally different. Radio waves, gamma-rays, visible light, and all the other parts of the electromagnetic spectrum are electromagnetic radiation.
Electromagnetic radiation can be described in terms of a stream of mass-less particles, called photons, each traveling in a wave-like pattern at the speed of light. Each photon contains a certain amount of energy. The different types of radiation are defined by the the amount of energy found in the photons. Radio waves have photons with low energies, microwave photons have a little more energy than radio waves, infrared photons have still more, then visible, ultraviolet, X-rays, and, the most energetic of all, gamma-rays.
Measuring electromagnetic radiation
Electromagnetic radiation can be expressed in terms of energy, wavelength, or frequency. Frequency is measured in cycles per second, or Hertz. Wavelength is measured in meters. Energy is measured in electron volts. Each of these three quantities for describing EM radiation are related to each other in a precise mathematical way. But why have three ways of describing things, each with a different set of physical units?
Comparison of wavelength, frequency and energy for the electromagnetic spectrum. (Credit: NASA’s Imagine the Universe)
The short answer is that scientists don’t like to use numbers any bigger or smaller than they have to. It is much easier to say or write “two kilometers” than “two thousand meters.” Generally, scientists use whatever units are easiest for the type of EM radiation they work with.
Astronomers who study radio waves tend to use wavelengths or frequencies. Most of the radio part of the EM spectrum falls in the range from about 1 cm to 1 km, which is 30 gigahertz (GHz) to 300 kilohertz (kHz) in frequencies. The radio is a very broad part of the EM spectrum.
Infrared and optical astronomers generally use wavelength. Infrared astronomers use microns (millionths of a meter) for wavelengths, so their part of the EM spectrum falls in the range of 1 to 100 microns. Optical astronomers use both angstroms (0.00000001 cm, or ) and nanometers (0.0000001 cm, or ). Using nanometers, violet, blue, green, yellow, orange, and red light have wavelengths between 400 and 700 nanometers. (This range is just a tiny part of the entire EM spectrum, so the light our eyes can see is just a little fraction of all the EM radiation around us.)
The wavelengths of ultraviolet, X-ray, and gamma-ray regions of the EM spectrum are very small. Instead of using wavelengths, astronomers that study these portions of the EM spectrum usually refer to these photons by their energies, measured in electron volts (eV). Ultraviolet radiation falls in the range from a few electron volts to about 100 eV. X-ray photons have energies in the range 100 eV to 100,000 eV (or 100 keV). Gamma-rays then are all the photons with energies greater than 100 keV.
Why do we put telescopes in orbit?
The Earth’s atmosphere stops most types of electromagnetic radiation from space from reaching Earth’s surface. This illustration shows how far into the atmosphere different parts of the EM spectrum can go before being absorbed. Only portions of radio and visible light reach the surface. (Credit: STScI/JHU/NASA)
Most electromagnetic radiation from space is unable to reach the surface of the Earth. Radio frequencies, visible light and some ultraviolet light makes it to sea level. Astronomers can observe some infrared wavelengths by putting telescopes on mountain tops. Balloon experiments can reach 35 km above the surface and can operate for months. Rocket flights can take instruments all the way above the Earth’s atmosphere, but only for a few minutes before they fall back to Earth.
For long-term observations, however, it is best to have your detector on an orbiting satellite and get above it all!
Updated: March 2013
