NASA uses earth as laboratory to study distant worlds

It is still possible to measure key characteristics of distant worlds.

These images show the sunlit side of Earth in 10 different wavelengths of light that fall within the infrared, visible and ultraviolet ranges; the images are representational-color, because not all of these wavelengths are visible to the human eye. Each wavelength highlights different features of the planet -- for example, the continent of Africa is visible in the lower right image, but is nearly invisible in the upper left image. These observations were obtained by NASA's Earth Polychromatic Imaging Camera (EPIC) instrument onboard the National Oceanic and Atmospheric Administration's Deep Space Climate Observatory, or DSCOVR, satellite, on Aug. 2, 2017. Credit: NASA/NOAA
These images show the sunlit side of Earth in 10 different wavelengths of light that fall within the infrared, visible and ultraviolet ranges; the images are representational-color, because not all of these wavelengths are visible to the human eye. Each wavelength highlights different features of the planet -- for example, the continent of Africa is visible in the lower right image, but is nearly invisible in the upper left image. These observations were obtained by NASA's Earth Polychromatic Imaging Camera (EPIC) instrument onboard the National Oceanic and Atmospheric Administration's Deep Space Climate Observatory, or DSCOVR, satellite, on Aug. 2, 2017. Credit: NASA/NOAA

In order to study exoplanets, scientists are trying their best to provide answers to big questions about our place in the universe, and whether life exists beyond Earth. I a new study by using NASA’s Earth Polychromatic Imaging Camera (EPIC) and Atmospheric Administration’s Deep Space Climate Observatory, or DSCOVR, satellite, NASA scientists show that even with very little light — as little as one pixel — it is still possible to measure key characteristics of distant worlds.

The DSCOVR circumvents the Sun at Lagrange point 1, an orbit that provides EPIC with a consistent perspective of our home planet’s sunlit surface. EPIC has been watching Earth ceaselessly since June 2015, creating nuanced maps of the planet’s surface in many wavelengths, and adding to investigations of atmosphere and climate.

The EPIC instrument captured reflected light from Earth in 10 distinct wavelengths, or colors. In this way, each time EPIC “takes a pictures” of Earth, it really captured 10 pictures. The new examination midpoints each picture into a single brightness esteem, or what might as well be called one “single-pixel” picture for every wavelength. A single, one-pixel preview of the planet would give almost no data about the surface.

Yet, in the new investigation, the creators dissected an informational collection containing single-pixel pictures taken various times each day, in 10 wavelengths, over a broadened period. However, the way that the planet had been decreased to a single point of light, the scientists could distinguish water clouds in the environment and measure the planet’s pivot rate (the length of its day).

According to scientists, the study exhibits that a similar data could be gotten from single-pixel perceptions of exoplanets.

This artist's illustration shows an enhanced-color image of Earth from NASA's Earth Polychromatic Imaging Camera (EPIC) instrument (top). EPIC observes the planet in 10 wavelength bands, shown here as 10 representational-color images (middle). A new study averages data from each EPIC wavelength band down into a single brightness value, or the equivalent of one "single-pixel" image. This allowed the study authors to simulate observations of a distant exoplanet. Credit: NASA/NOAA/JPL-Caltech
This artist’s illustration shows an enhanced-color image of Earth from NASA’s Earth Polychromatic Imaging Camera (EPIC) instrument (top). EPIC observes the planet in 10 wavelength bands, shown here as 10 representational-color images (middle). A new study averages data from each EPIC wavelength band down into a single brightness value, or the equivalent of one “single-pixel” image. This allowed the study authors to simulate observations of a distant exoplanet. Credit: NASA/NOAA/JPL-Caltech

Jonathan Jiang, an atmospheric and climate scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, and lead author on the new study said, “The benefit of using Earth as a proxy for an exoplanet is that we can verify our conclusions derived from the single-pixel data with the wealth of data that we actually have for Earth — we can’t do that if we’re using data from a distant, actual exoplanet.”

This image shows the sunlit side of Earth, observed in 10 wavelengths by the EPIC instrument aboard the DSCOVR satellite. Each image shows the same snapshot of Earth in a different wavelength. The specific wavelength bands are indicated above each image. Credit: NASA/NOAA
This image shows the sunlit side of Earth, observed in 10 wavelengths by the EPIC instrument aboard the DSCOVR satellite. Each image shows the same snapshot of Earth in a different wavelength. The specific wavelength bands are indicated above each image. Credit: NASA/NOAA

While explaining to Jiang daughter and her friends, in elementary school, he organized a star-observing event. Pointing towards the stars, he explained sun is also a star and that there are planets orbiting other stars just as planets orbit the Sun.

Jiang said, “Kids ask a lot of good questions. One of them including how scientists could possibly learn about those distant worlds from such tiny points of light in the sky. And that question stuck in my mind — if I can see an exoplanet as only a tiny point of light, can I see clouds and oceans and land?”

This animation shows a series of observations taken by the EPIC instrument in one of 10 wavelengths. At this wavelength, the distinction between continents and oceans is particularly visible. The repeating pattern created by the planet's rotation could be observable to a powerful telescope observing the planet from many light years away, according to a new study. Credit: NASA/NOAA
This animation shows a series of observations taken by the EPIC instrument in one of 10 wavelengths. At this wavelength, the distinction between continents and oceans is particularly visible. The repeating pattern created by the planet’s rotation could be observable to a powerful telescope observing the planet from many light years away, according to a new study. Credit: NASA/NOAA

During the study, scientists also used climate data to assist the study of exoplanets.

Jiang said, “The new study shows that by observing a planet with distinct features over time — such as oceans and continents — it is possible to measure the planet’s rotation rate by observing a repeating pattern in the reflected light. This pattern would arise from those planetary features moving into view with a regular cadence. For example, every 24 hours, Australia and the Pacific Ocean fills EPIC’s field of view, and about 12 hours later South America and the Atlantic fill the frame, with Africa and the Indian Ocean passing by in between. This pattern of changing light would repeat day after day. In the new paper, the authors show that they can detect this repeating cycle and thus determine the rotation rate, or the length of the planet’s day. The rotation rate of a planet can reveal information about how and when the planet formed and is a particularly difficult property to measure with current methods.”

This image, taken by NASA's Voyager 1 spacecraft from beyond the orbit of Neptune, shows planet Earth as seen from about 3.7 billion miles (5.9 billion km) away. Earth appears as a very small point of light in the right half of the image, indicated by an arrow. Dubbed the "Pale Blue Dot," the image illustrates just how small an Earth-sized planet appears from far away. Credit: NASA/JPL-Caltech
This image, taken by NASA’s Voyager 1 spacecraft from beyond the orbit of Neptune, shows planet Earth as seen from about 3.7 billion miles (5.9 billion km) away. Earth appears as a very small point of light in the right half of the image, indicated by an arrow. Dubbed the “Pale Blue Dot,” the image illustrates just how small an Earth-sized planet appears from far away. Credit: NASA/JPL-Caltech

Renyu Hu, an exoplanet scientist at JPL and a co-author on the new study said, “People have been talking for some time about using this approach to measure the rotation rate of exoplanets, but there’s been no demonstration that it could work because we didn’t have any real data. We’ve shown that in every wavelength, the 24-hour period appears, which means this approach to measuring planet rotation is robust.”