Scott Alan Johnston, Author at Universe Today

January 1, 2022January 1, 2022 by Scott Alan Johnston

2029 Will be the Perfect Year to Launch a Mission to Sedna

Artist's conception of Sedna, the TNO that orbits in the outer edges of the Solar System. Credit: NASA/JPL-Caltech

Object 90377 Sedna – a distant trans-Neptunian object known best for its highly elliptical, 11,390-year long orbit – is currently on its way towards perihelion (its closest approach to the Sun) in 2076. After that, Sedna will swing out into deep space again and won’t be back for millennia, making this flyby a once-in-a-lifetime (or, once in ~113 lifetimes) opportunity to study an object from the far reaches of our solar system. There are no missions to Sedna in the works just yet, but astronomers are beginning to plan for the possibility, and the ideal launch date for such a mission is approaching fast, with two of the best launch windows coming up in 2029 and 2034.

December 22, 2021December 22, 2021 by Scott Alan Johnston

Life Could Make Habitable Pockets in Venus’ Atmosphere

Venus' thick clouds mean that only radar imaging can reveal surface details. Image Credit: NASA/JPL-Caltech

The tantalizing possibility that life exists in the clouds of Venus is once again causing a stir amongst planetary scientists this week. Researchers out of the Massachusetts Institute of Technology, Cardiff University, and the University of Cambridge have proposed that some longstanding ‘anomalies’ in the composition of Venus’ atmosphere might be explained by the presence of ammonia. But ammonia itself would be a strange compound to discover there, unless some unknown process – such as biological life – was actively producing it. Perhaps more intriguingly, ammonia can remove the acidity from Venus’ hostile cloud-tops, suggesting that an airborne, ammonia-producing microbe might have evolved the ability to turn its hostile surroundings into something habitable.

December 16, 2021December 16, 2021 by Scott Alan Johnston

NASA has 4 new Earth Science Missions Launching in 2022

Outer space is a great place to go if you want to study the Earth. Although outward-looking spacecraft like Hubble and the highly anticipated James Webb Space Telescope garner most of the attention from the public – understandably, given their spectacular imagery of distant astronomical phenomena – the large majority of satellite infrastructure in orbit is actually focused back on our home planet. The unparalleled view of the planet from space offers unique advantages to scientists hoping to measure changes and patterns here on Earth that just aren’t possible from the ground. In 2022, NASA will launch four new Earth science missions, each offering something unique, and adding a new way to understand, and protect, our home.

let’s take a look at the four missions, and what they hope to achieve in the coming years.

December 5, 2021December 5, 2021 by Scott Alan Johnston

If There are Water Plumes on Europa, Here’s how Europa Clipper Will Study Them

NASA’s Europa Clipper is one of the most anticipated missions of the coming decade, in large part because its target, the large Jovian moon Europa, is considered one of the most likely places in our solar system that extraterrestrial life might exist. If Europa is harboring alien microbes, however, they’re likely to be buried deep beneath the moon’s thick icy crust in a vast subsurface ocean. Unlocking the secrets of this water world isn’t going to be easy, but the Clipper team has a plan to make the most of the opportunity they have: If you can’t get to the ocean, let the ocean come to you.

November 27, 2021November 27, 2021 by Scott Alan Johnston

It’s Time to Stop Doing Anti-Satellite Tests

This image from the ESA's MASTER (Meteoroid and Space Debris Terrestrial Environment Reference) risk-assessment tool shows the dangerous debris orbiting Earth. Image Credit: IRAS/TU Braunschweig

Earlier this month, the Russian military conducted an anti-satellite (ASAT) missile test, launching a PL19 Nudol interceptor missile at a now-defunct Soviet-era intelligence satellite, KOSMOS 1408. The impact obliterated the spacecraft, creating a debris field consisting of approximately 1500 pieces of trackable debris, and potentially hundreds of thousands of pieces that are too small to monitor with ground-based radar. In the aftermath of the test, the debris field crossed the orbit of the International Space Station (ISS) repeatedly, causing the crew to take emergency precautions and shelter in their descent capsules, ready for a quick return to Earth in the event that the station was hit.

While the station and its crew escaped without harm this time around, the November 15 test demonstrated far too clearly that ASATs pose a real danger to human life. They can also wreak havoc on the rest of Earth’s space infrastructure, like communications satellites and other orbital systems. Debris from an ASAT test remains in orbit long after the initial incident is over (the higher the orbit, the longer lasting the debris), and if humanity’s space infrastructure is to be sustainable, the era of ASATs must come to an end, and soon.

November 21, 2021November 21, 2021 by Scott Alan Johnston

We’re Constantly Battling Invasive Species Here on Earth. What Does That Teach us About Infecting Other Worlds With Earth Life?

When Neil Armstrong, Buzz Aldrin, and Michael Collins returned from the Moon in the summer of 1969, they spent three weeks isolated in quarantine to make sure that they hadn’t brought back any microbial lifeforms from the Moon, which could prove harmful to Earth life. Later, once the Moon had been unequivocally proved to be a dead world, future Apollo missions were allowed to skip quarantine. Elsewhere in the solar system, however, NASA still has to take planetary biosecurity seriously, because life could be out there. If we bring it back to Earth, it could be a danger to us and our ecosystems. Conversely, microbial Earth life could invade a fragile alien ecosystem, destroying a newly discovered lifeform before we have the chance to study it. Imagine discovering life on Mars, only to realize that it was life we had brought there with us.

November 11, 2021November 11, 2021 by Scott Alan Johnston

Fungi Were Able to Absorb Radiation on the ISS. Could Astronauts Grow Their own Radiation Shields in Space?

A lack of effective radiation shielding is one of the biggest challenges still to be overcome if humans are to embark on long-term voyages into deep space. On Earth, the planet’s powerful magnetosphere protects us from the deadliest forms of radiation – those produced by solar flares, and galactic cosmic rays arriving from afar – that stream through the Solar System. Astronauts on the International Space Station, some 408km above the Earth, receive elevated levels of radiation, but are close enough to Earth that they still receive some shielding, and can stay on orbit for up to a year. The same can’t be said for astronauts traveling further out, to the Moon, for example, or, someday, to Mars. Future deep space voyagers will need to bring their own shielding with them – or, as a new paper suggests – grow it along the way.

October 30, 2021October 30, 2021 by Scott Alan Johnston

Artemis 1 is Launching in February

It’s been a long time coming, but NASA’s next moon rocket is just months from liftoff on its first uncrewed test flight. The Space Launch System (SLS) is a super heavy-lift vehicle capable of delivering 95 tons to Low Earth Orbit, but its primary purpose will be to deliver humans to lunar orbit and, eventually, to the lunar surface. SLS has been in development since 2011, and it’s faced a series of delays, but launch day is finally within sight. Earlier this month, the rocket was fully stacked for the first time in the Vehicle Assembly Building at the Kennedy Space Center, and the Orion capsule (the spacecraft’s crew cabin) was attached to the top. The full stack stands an impressive 322 feet tall, just shy of the Saturn V’s 363 feet.

October 17, 2021October 17, 2021 by Scott Alan Johnston

Did Titan Give Saturn its Tilt?

Giant planets like Saturn don’t just tilt over all by themselves: something has to knock them over, or tug on them gravitationally, to push them off axis. Scientists expect that when new planets are born, they form with almost no tilt at all, lining up like spinning tops, with their equators level to the orbital plane in which they circle around their sun.

But no planet in our solar system is perfectly level. Jupiter is the closest, boasting an obliquity (tilt) of just 3.12 degrees. Earth’s obliquity is much more substantive at 23.45 degrees, causing us to experience an annual cycle of seasons as our homeworld wobbles on its axis. Saturn’s tilt is more extreme yet, with an obliquity of 26.73 degrees (though it’s nowhere near as extreme as Uranus, which is practically sideways, spinning at a 97.86-degree angle to its orbital plane).

We can learn a lot from these obliquities.

October 7, 2021October 7, 2021 by Scott Alan Johnston

Perseverance Sees Evidence of Flash Floods in Jezero Crater

Nearly eight months into the Perseverance rover’s mission on Mars, researchers have confirmed that Jezero crater is (as was believed) an ancient lakebed, but more significantly, that it once experienced powerful flash floods that pushed boulders from tens of miles upstream into the crater basin.