Earth Archives

March 13, 2023March 13, 2023 by Matt Williams

A Human Migration to Space is NOT so Inevitable, says New Research

Artist's depiction of a pair of O'Neill cylinders. Credit: Rick Guidice/NASA Ames Research Center

“It is possible even with existing technology, if done in the most efficient ways. New methods are needed, but none goes beyond the range of present-day knowledge. The challenge is to bring the goal of space colonization into economic feasibility now, and the key is to treat the region beyond Earth not as a void but as a culture medium, rich in matter and energy. Then, in a time short enough to be useful, the exponential growth of colonies can reach the point at which the colonies can be of great benefit to the entire human race.”

-Gerard K. O’Neill, The Colonization of Space, 1974

During the 1960s and 70s, coinciding with the height of the Space Age, scientists pondered how human beings could one day live in space. Among the many benefits, the migration of humans and industry to other celestial bodies and orbiting habitats presented a possible solution to overpopulation and environmental degradation. As O’Neill suggested in his writings, the key was to make this migration an economically feasible venture. Given the renewed efforts to explore space that are now underway and the rise of commercial space (NewSpace), there is a growing sense that humanity’s migration to space is within reach – and even inevitable.

But to paraphrase famed British historian AJP Taylor, “nothing is inevitable until it happens.” In a new study, Cornell graduate researcher Morgan A. Irons and Norfolk Institute co-founder and executive director Lee G. Irons reviewed a century of scientific studies to develop the Pancosmorio (“World Limit”) theory. They concluded that specific life-sustaining conditions on Earth that are available nowhere else in the Solar System could be the very thing that inhibits our expansion into space. Without an Earth-like “self-restoring order, capacity, and organization,” they argue, space settlements would fail to be sustainable and collapse before long.

March 10, 2023March 10, 2023 by Evan Gough

Water’s Epic Journey to Earth Began Before the Sun Formed

This artist’s impression shows the planet-forming disc around the star V883 Orionis. New research shows how water starts its journey in the gas cloud that forms the star, and eventually ends its journey on Earth. Image Credit: ESO/L. Calçada

The origins of Earth’s water is a complicated mystery that scientists have been untangling for decades. Life is impossible without water, so the origin of Earth’s life-giving water is a foundational question. As the power of our telescopes grows, researchers have made meaningful headway on the question.

Previous research uncovered links between Earth’s water and the Solar System’s comets and icy planetesimals. But newer research follows the chain back even further in time to when the Sun itself had yet to form.

March 5, 2023March 5, 2023 by Matt Williams

The Earth has an Even More Inner Core, and it's a Ball of Solid Metal

The Earth's layers, showing the Inner and Outer Core, the Mantle, and Crust. Credit: discovermagazine.com

For generations, scientists have probed the structure and composition of the planet using seismic wave studies. This consists of measuring shock waves caused by Earthquakes as they penetrate and pass through the Earth’s core region. By noting differences in speed (a process known as anisotropy), scientists can determine which regions are denser than others. These studies have led to the predominant geological model that incorporates four distinct layers: a crust and a mantle (composed largely of silicate minerals) and an outer core and inner core composed of nickel-iron.

According to seismologists from The Australian National University (ANU), data obtained in a recent study has shed new light on the deepest parts of Earth’s inner core. In a paper that appeared in Nature Communications, the team reports finding evidence for another distinct layer (a solid metal ball) in the center of Earth’s inner core – an “innermost inner core.” These findings could shed new light on the evolution of our planet and lead to revised geological models of Earth that include five distinct layers instead of the traditional four.

March 3, 2023March 3, 2023 by Nancy Atkinson

Why are Earth’s Hemispheres the Same Brightness? New Research Solves a 50-year-old Mystery.

The Blue Marble from Apollo 17 — The Blue Marble image of Earth from Apollo 17. Credit: NASA

NASA’s Apollo program most notably explored the Moon. But it also helped us study the Earth as well, as it provided some of the first high-resolution images of our whole planet, like the famous “Blue Marble” photo taken by the Apollo 17 astronauts.

However, these full-Earth photos revealed a mystery. Scientists expected that Earth’s two hemispheres, the north and south, would have different albedos, a difference in the amount of light they reflect. This is because Earth’s northern and southern hemispheres of Earth are quite different from each other. The southern hemisphere is mostly covered with dark oceans, while the northern hemisphere contains vast land areas that are much brighter than the oceans

Yet, when observing Earth from space, the two hemispheres appear equally bright.

This symmetry in brightness has been a puzzle for over 50 years. But now, a new study shows that the albedos are roughly the same because of the increased clouds and storms in the southern hemisphere.

January 21, 2023January 21, 2023 by Andy Tomaswick

A new Propulsion System Could Levitate Vehicles in the Earth’s Upper Atmosphere

Sometimes it’s hard to remember that NASA also does atmospheric research too. While typically thought of as the province of the National Oceanic and Atmospheric Administration (NOAA), America’s space agency also has a vested interest in exploring our atmosphere and in the technologies that enable us to do so. As such, its NASA Institute for Advanced Concepts (NIAC) program provided a Phase I grant to a team from the University of Pennsylvania to develop a novel type of propulsion using only light to collect data in the Earth’s challenging-to-explore mesosphere.

January 20, 2023January 20, 2023 by Evan Gough

Light Pollution is Obscuring the Night Sky. RIP Stargazing

A startling analysis from Globe at Night — a citizen science program run by NSF’s NOIRLab — concludes that stars are disappearing from human sight at an astonishing rate. Image Credit: NOIRLab/NSF/AURA, P. Marenfeld

A citizen science initiative called Globe at Night has some sobering news for humanity. Our artificial light is drowning out the night sky for more and more people. And it’s happening more rapidly than thought.

January 18, 2023January 18, 2023 by Evan Gough

Could Next-Generation Telescopes See That Earth Has Life?

In this image, Earthshine lights up the dark portion of the lunar surface. Image Credit: NASA

While the Earth absorbs a lot of energy from the Sun, a lot of it is reflected back into space. The sunlight reflected from Earth is called Earthshine. We can see it on the dark portion of the Moon during a crescent Moon. The Farmer’s Almanac said it used to be called “the new Moon in the old Moon’s arms.”

Earthshine is one instance of planetshine, and when we look at the light from distant exoplanets, we’re looking directly at their planetshine without it bouncing off another object.

If distant astronomers were looking at Earthshine the way we look at exoplanet shine, would the light tell them our planet is rippling with life?

December 29, 2022December 29, 2022 by Evan Gough

Should Planetary Defence Take Center Stage?

This illustration shows NASA's NEO Surveyor against an infrared observation of a starfield made by the agency's WISE mission. NEO Surveyor is the first purpose-built space telescope that will advance NASA’s planetary defense efforts by finding and tracking hazardous near-Earth objects. Credit: NASA/JPL-Caltech/University of Arizona

Throughout the Solar System, planets and moons bear the scars of a past fraught with collisions. The Moon, Mercury, and Mars are so scarred from these impacts that craters overlap one another on their surfaces. Earth was subject to the same bombardment, though most of its impact scars disappeared over time due to active geology.

But some are still visible, and we know how catastrophic some of these impacts were for life.

December 15, 2022December 16, 2022 by Evan Gough

Earth’s Water is 4.5 Billion Years Old

A protosolar disk is the disk of material around a young stellar object that isn't yet a star. It's called a protoplanetary disk once the star has formed and begun fusion. Planetesimals are the building blocks of planets and are present in both stages of a disk's evolution. Image Credit: NASA/JPL

The origin of Earth’s water has been an enduring mystery. There are different hypotheses and theories explaining how the water got here, and lots of evidence supporting them.

But water is ubiquitous in protoplanetary disks, and water’s origin may not be so mysterious after all.

December 10, 2022December 10, 2022 by Scott Alan Johnston

To Fight Climate Change, We Could Block the Sun. A Lightweight Solar Sail Could Make it Feasible

Could a solar-sail-like structure (or structures) tethered to an asteroid provide a sunshade for Earth to block sunlight and mitigate climate change? A recent study looks into it. Courtesy NASA.

Can we build an enormous umbrella to dim the Sun? Such a feat would be a megaproject on a scale like no other. It would take at least 400 dedicated rocket launches a year, for ten years (There have been 172 rocket launches by all nations so far in 2022). The project would weigh in at 550,000 tons: at its lightest. And it would be an ecological experiment that puts us all – the entire planet – in the petri dish, with high risk and high reward. But could such a project actually reverse climate change and bring us back from the brink of global disaster?

The answer seems to be yes, it could work. But there are consequences, and with the planet at stake, it seems wise to examine them before committing to such a thing.