Space and astronomy news
The source of Earth’s water is an enduring mystery that extends to exoplanets and the notion of habitability. In broad terms, Earth’s water was either part of the planet from the beginning of its formation in the solar nebula or delivered later, maybe by asteroids and comets.
New research suggests that the Sun’s relentless solar wind could’ve played a role.
Continue reading “Did Some of Earth’s Water Come from the Solar Wind?”
Panspermia is an innately attractive idea that’s gained prominence in recent decades. Yet, among working scientists, it gets little attention. There are good reasons for their relative indifference, but certain events spark renewed interest in panspermia, even among scientists.
The appearance of Oumuamua in our Solar System in 2017 was one of them.
Continue reading “How Oumuamua Changes Our Perspective on Galactic Panspermia”
Untangling what happened in our Solar System tens or hundreds of millions of years ago is challenging. Millions of objects of wildly different masses interacted for billions of years, seeking natural stability. But its history—including the migration of the giant planets—explains what we see today in our Solar System and maybe in other, distant solar systems.
New research shows that giant planet migration began shortly after the Solar System formed.
Continue reading “The Giant Planets Migrated Between 60-100 Million Years After the Solar System Formed”
According to the most widely accepted scientific theory, our Solar System formed from a nebula of dust and gas roughly 4.56 billion years ago (aka. Nebula Theory). It began when the nebula experienced gravitational collapse at the center, fusing material under tremendous pressure to create the Sun. Over time, the remaining material fell into an extended disk around the Sun, gradually accreting to form planetesimals that grew larger with time. These planetesimals eventually experienced hydrostatic equilibrium, collapsing into spherical bodies to create Earth and its companions.
Based on modern observations and simulations, researchers have been trying to understand what conditions were like when these planetesimals formed. In a new study, geologists from the California Institute of Technology (Caltech) combined meteorite data with thermodynamic modeling to better understand what went into these bodies from which Earth and the other inner planets formed. According to their results, the earliest planetesimals have formed in the presence of water, which is inconsistent with current astrophysical models of the early Solar System.
Continue reading “The Meteorites That Made Earth Were Filled With Water”
Venus and Earth have several things in common. Both are terrestrial planets composed of silicate minerals and metals that are differentiated between a rocky mantle and crust and a metal core. Like Earth, Venus orbits within our Sun’s circumsolar habitable zone (HZ), though Venus skirts the inner edge of it. And according to a growing body of evidence, Venus has active volcanoes on its surface that contribute to atmospheric phenomena (like lightning). However, that’s where the similarities end, and some rather stark differences set in.
In addition to Venus’ hellish atmosphere, which is about 100 times as dense as Earth’s and hot enough to melt lead, Venus has a very “youthful” surface. Compared to other bodies in the Solar System (like Mercury, the Moon, and Mars), Venus’ surface retains little evidence of the many bolides impacts it experienced over billions of years. According to new research from the Southwest Research Institute (SwRI) and Yale University, this may result from bolide impacts that provided a high-energy, rejuvenating boost to the planet in its early years.
Continue reading “Did Powerful Asteroid Impacts Make Venus So Different From Earth?”
With its thick, cloudy atmosphere, Venus has long held mysteries about its surface. It was only in the late 20th century that astronomers had detailed observations of the Venusian landscape, with the Russian Venera landers in the 1970s and 1980s, and later the 1990 Magellan mission, which made high-resolution radar maps of the surface. There are many things we still don’t know, but one thing we do know is that the surface of Venus is young. And a new study in Nature Astronomy may know why.
Continue reading “Venus Needed Asteroid Impacts to Get its Volcanoes Going”
On Mars, NASA’s Perseverance rover is busy collecting rock samples that will be retrieved and brought back to Earth by the Mars Sample Return (MSR) mission. This will be the first sample-return mission from Mars, allowing scientists to analyze Martian rocks directly using instruments and equipment too large and cumbersome to send to Mars. To this end, scientists want to ensure that Perseverance collects samples that satisfy two major science goals – searching for signs of life (“biosignatures”) and geologic dating.
To ensure they select the right samples, scientists must understand how rock samples formed and how they might have been altered over time. According to a new NASA study, Martian rocks may have been “shocked” by meteorite impacts during its early history (the Late Heavy Bombardment period). The role these shocks played in shaping Martian rocks could provide fresh insights into the planet’s geological history, which could prove invaluable in the search for evidence of past life on Mars.
Continue reading “How are Mars Rocks Getting “Shocked” by Meteorite Impacts?”
Today, Mars is colloquially known as the “Red Planet” on a count of how its dry, dusty landscape is rich in iron oxide (aka. “rust”). In addition, the atmosphere is extremely thin and cold, and no water can exist on the surface in any form other than ice. But as the Martian landscape and other lines of evidence attest, Mars was once a very different place, with a warmer, denser atmosphere and flowing water on its surface. For years, scientists have attempted to determine how long natural bodies existed on Mars and whether or not they were intermittent or persistent.
Another important question is how much water Mars once had and whether or not this was enough to support life. According to a new study by an international team of planetary scientists, Mars may have had enough water 4.5 billion years ago to cover it in a global ocean up to 300 meters (almost 1,000 feet) deep. Along with organic molecules and other elements distributed throughout the Solar System by asteroids and comets at this time, they argue, these conditions indicate that Mars may have been the first planet in the Solar System to support life.
Continue reading “Mars Once had Enough Water for a Planet-Wide Ocean 300 Meters Deep”
It’s no secret that Earth was bombarded with plenty of meteors for billions of years during the solar system’s early formation. Estimates vary on how much material impacted the planet, but it had a considerable effect on the planet’s atmosphere and the evolution of life. Now, a new study from a team led by researchers at the Southwest Research Institute puts the number at almost ten times the number of previously estimated impacts. That much of a difference could dramatically change how geologists and planetary scientists view the early Earth.
Continue reading “Early Earth was Pummeled 10x More Than Previously Estimated”
The early solar system was an especially violent place. The terrestrial planets (Mercury, Venus, Earth, and Mars) likely formed by suffering countless collisions between planetesimals. But the material left over from all those collisions should have remained in orbit around the sun, where it would’ve eventually found itself in the asteroid belt. But the belt contains no such record of that process.
Continue reading “There Should be More Material Left Over From Bombardment Eras. Maybe the Sun Blew it all Away?”