Science

Forget Megalopolis and Madame Web. The best science fiction films of the year were all horror-inflected, says our film columnist Simon Ings

Alternative thinking on the evolution of species is a welcome way to highlight some neglected aspects of life on Earth, but it doesn't mean Darwin was wrong

Radiation is a primary concern for long-duration human spaceflight, such as the planned trips to Mars, which are the stated goal of organizations such as NASA and SpaceX. Shielding is the standard way to protect astronauts from radiation during those flights. However, shielding is heavy and, therefore, expensive when it is launched off the Earth. What if, instead, astronauts could hitch a ride on a giant mass of shielding already in space that will take them directly to their destination? That is the basic thought behind a paper from Victor Reshetnyk and his student at Taras Shevchenko National University in Kyiv. 

They looked at data collected by NASA’s Horizons service and analyzed the orbits of over 35,000 Near Earth Objects (NEOs) for their trajectories to see if their paths would cross somewhere between the binary pairs of Earth-Venus, Earth-Mars, or Mars-Venus. If so, then in theory, they could be used as shielding from the deadly radiation astronauts would have to either suffer from or shield against on the trip.

Given the sheer amount of objects they looked at, they were bound to find some good candidates – and they did, with an estimated 525 making “fast” transfers of less than 180 days. They then further narrowed this list down to a reasonable speed during the approach to the planet they would start from – essentially to make sure that a crewed spacecraft could actually catch up to the asteroid without burning an absurd amount of fuel.

Fraser discusses how to make an asteroid a habitat.

That lowered the total amount of candidates down to 120, with the following breakdown:

• Earth -> Venus: 44
• Earth -> Mars: 17
• Mars -> Earth: 13
• Mars -> Venus: 2
• Venus -> Earth: 38
• Venus -> Mars: 6

In other words, there were plenty of options for hitching a ride. Granted, none of these would be exceptionally roomy – the largest is estimated to have a diameter of only .37 km. However, there is still plenty of room to fit a spaceship, as long as it’s not a Star Destroyer or Battleship from 40K.

Additionally, the authors found some asteroids that had more unique trajectories. Eleven had the possibility of doing “multiple” transfers, meaning they could go from Earth to Venus and then back or vice versa, but only one would do the same for the Venus to Mars trip. Two could even do a “double” transfer, meaning they could go from Earth to Venus to Mars or from Mars to Venus to Earth in less than one year. Anything beyond that wasn’t possible, though – they didn’t find any asteroids akin to an “Aldrin Cycler” that would go between the planets indefinitely on a known orbit.

Capturing an asteroid would be one way to use it for shielding – as Fraser discusses.

That’s not to say that asteroid doesn’t already exist – we might just not have found it yet. NEO Surveyor, a NASA mission designed to launch in 2028 to find 90% of all NEOs larger than 140m in diameter, could increase the number of known NEOs by an order of magnitude.

Using any of them for a massive radiation shield for a crewed mission would take much more dedicated work, though. Any such transformation is decades away at least – but the place to start is to find the right ones, and this paper contributes to that effort.

Learn More:
A.S. Kasianchuk & V. M. Reshetnyk – The search for NEOs as potential candidates for use in space missions to Venus and Mars
UT – A New Paper Shows How To Change An Asteroid Into A Space Habitat – In Just 12 Years
UT – Rubble Pile Asteroids Might be the Best Places to Build Space Habitats
UT – NASA Makes Asteroid Defense a Priority, Moving its NEO Surveyor Mission Into the Development Phase

Lead Image:
Illustration of the asteroid Bennu.
Credit: NASA Jet Propulsion Laboratory

The post Could We Use An Asteroid to Shield Astronauts On Their Way to Mars? appeared first on Universe Today.

Today’s Jesus and Mo strip, called “cursed,: came with the note, “It’s Tahir Ali MP.” The link goes to Mr. Ali calling for blasphemy laws protecting all religious texts, including of course the Qur’an.

Jesus’s logic gets Mo all balled up, and in the end Mo gets to the real point of Ali’s proposal

Large-scale production of organic solar cells with high efficiency and minimal environmental impact. In the study, the researchers studied molecule shape and interaction in organic solar cells.

Two massive asteroids hit Earth around 35.65 million years ago, but did not lead to any lasting changes in the Earth's climate, according to a new study.

Scientists carried out an experiment that realizes a new kind of quantum standard of resistance. It's based on the Quantum Anomalous Hall Effect.

Scientists carried out an experiment that realizes a new kind of quantum standard of resistance. It's based on the Quantum Anomalous Hall Effect.

Chemical engineers designed a catalyst that can convert methane into useful polymers, which could help reduce greenhouse gas emissions.

Fiber optics are a means of transmitting information at incredibly high speeds; however, the technology can be used for more than just providing a fast internet connection. Researchers have developed an optical fiber sensing system that could help medical professionals monitor patients for complications after a traumatic brain injury. The technology tracks six biomarkers simultaneously, continuously and automatically to provide crucial information on brain health in lab tests.

Undocumented orphaned wells pose hazards to both the environment and the climate. Scientists are building modern tools to help locate, assess, and pave the way for ultimately plugging these forgotten relics.

Undocumented orphaned wells pose hazards to both the environment and the climate. Scientists are building modern tools to help locate, assess, and pave the way for ultimately plugging these forgotten relics.

Researchers have uncovered a serious side effect of using the CRISPR-Cas gene scissors. A molecule designed to make the process more efficient destroys parts of the genome.

A large study, of 77 deceased male ice hockey players, has found that the odds of having chronic traumatic encephalopathy (CTE) increased by 34% each year played, and 18 of 19 National Hockey League players had CTE. CTE is a neurodegenerative disease caused by repeated traumatic brain injuries and most frequently found in former contact sport athletes exposed to repetitive head impacts (RHI). While many perceive CTE risk as limited to enforcers, this study makes it clear that all male ice hockey players are at risk.

Astrophysicists find the birth sites of gigantic elliptical galaxies which they say gives new clues about how they were formed. The galaxies look like bulging footballs and how they were created remains a mystery to scientists -- until now.

Although they are very different today, Venus, Earth, and Mars were very similar in their youth. All three were warm, with thick, water-rich atmospheres. But over time, Mars became a cold, dry planet with a thin atmosphere, and Venus became superheated, with a crushing, toxic sky. Only Earth became a warm ocean world teeming with life. But why?

We know that Mars once had vast seas. It had the right conditions for life in the beginning, but with less gravity than Earth and a weak magnetic field, Mars lost much of its atmosphere over time, and most of its water either froze beneath the surface or became chemically locked in Martian clay. If Mars had been larger and more geologically active, perhaps it would have become another living world.

Which raises the question of Venus. In terms of mass and composition, Venus seems to be nearly a twin of Earth. Its surface gravity is 90% of Earth’s. While it doesn’t have a strong magnetic field like our world, it is geologically active. We can even see evidence of volcanic activity on its surface. Venus also retained a thick atmosphere, so why is it a hell-world compared to Earth?

The most common model of early Venus is that the planet was Earth-like once. Its water-rich atmosphere would have rained upon the surface to create warm seas and rivers, just like Earth and Mars. Some models suggest that Venus could have been Earth-like until 700 million years ago. But eventually, either because of its proximity to the Sun, a lack of magnetic field, or some geological process, Venus underwent a greenhouse transformation. Its oceans dried, and its atmosphere thickened to become the deadly world we see today. Perhaps we on Earth should look at Venus as a cautionary tale of what happens when greenhouse gases dramatically increase.

Two possible histories of Venus. Credit: Constantinou, et al

But new research argues that Venus was never a wet world. While it did have a water-rich early atmosphere early on, it never retained the water, and seas never formed on our planetary sibling.

The study begins by calculating the rate at which water, carbon dioxide, and other molecules are decomposed within the atmosphere. Ultraviolet radiation striking the upper atmosphere as well as chemical interactions can break apart these molecules. To maintain stable levels of water, for example, it must be replenished through volcanic activity.

On Earth, the volcanic gases released are mostly water vapor because Earth’s interior is rich in water. This allows our planet to replace water that decomposes in our upper atmosphere. But the interior of Venus is much more dry, with only 6% of the gases being water vapor. The rest is mostly carbon dioxide and sulfur compounds. In this model, the composition of volcanic gases is the main driver of how a planet’s atmosphere evolves, not the initial composition of the atmosphere. So, with little volcanic activity, the atmosphere of Mars thinned. With dry, sulfur-rich volcanic gases, Venus became a greenhouse world. With water-rich volcanic gases, Earth remained an ocean planet.

Currently, there is evidence for both evolutionary models on Venus, and neither can be ruled out. Future projects such as NASA’s DAVINCI mission could give us a richer view of the Venusian atmosphere, but until then, it remains to be seen whether the fate of a planet is written in its rock or its sky.

Reference: Constantinou, Tereza, Oliver Shorttle, and Paul B. Rimmer. “A dry Venusian interior constrained by atmospheric chemistry.” Nature Astronomy (2024): 1-10.

The post Maybe Venus Was Never Habitable appeared first on Universe Today.

An analysis of ancient cuneiform texts suggests people thought of emotions in a different way almost 3000 years ago, showing how culture influences our most intimate experiences

The latest weather forecasting AI model from Google DeepMind can beat the leading providers more than 97 per cent of the time, and it is quicker and cheaper to run

A bird-inspired robot called RAVEN can walk, hop and jump into flight, an ability that could help people develop fixed-wing drones that can take off and land anywhere

Natural selection isn't just something that happens to organisms, their activities also play a role, giving some species – including humans – a supercharged ability to evolve