NASA Astronomy Picture of the Day

Mar 30, 2024

Medieval Astronomy from Melk Abbey

Discovered by accident, this manuscript page provides graphical insight to astronomy in medieval times, before the Renaissance and the influence of Nicolaus Copernicus, Tycho de Brahe, Johannes Kepler, and Galileo. The intriguing page is from lecture notes on astronomy compiled by the monk Magister Wolfgang de Styria before the year 1490. The top panels clearly illustrate the necessary geometry for a lunar (left) and solar eclipse in the Earth-centered Ptolemaic system. At lower left is a diagram of the Ptolemaic view of the Solar System with text at the upper right to explain the movement of the planets according to Ptolemy's geocentric model. At the lower right is a chart to calculate the date of Easter Sunday in the Julian calendar. The illustrated manuscript page was found at historic Melk Abbey in Austria.

https://apod.nasa.gov/apod/astropix.html?

Polar vortex is 'spinning backwards' above Arctic after major reversal event

Mar 30, 2024

The polar vortex circling the Arctic is swirling in the wrong direction after surprise warming in Earth's atmosphere triggered a major reversal event earlier this month. It is one of the most extreme atmospheric U-turns seen in recent memory.

In the past, disruptions to the polar vortex — a rotating mass of cold air that circles the Arctic — have triggered extremely cold weather and storms across large parts of the U.S..

The current change in the vortex's direction probably won't lead to a similar "big freeze." But the sudden switch-up has caused a record-breaking "ozone spike" above the North Pole.

The polar vortex is most prominent during winter months and extends into the stratosphere — the second layer of the atmosphere up to around 30 miles (50 kilometers) above the surface. The vortex spins counterclockwise with wind speeds of around 155 mph (250 km/h), which is around the same speed as a Category 5 hurricane, according to the U.K. Met Office. A similar vortex also encircles Antarctica during the southern winter.

Polar vortices occasionally reverse temporarily. These events can last for days, weeks or months and are caused by sudden stratospheric warming (SSW), when the temperatures in the stratosphere climb by as much as 90 degrees Fahrenheit (50 degrees Celsius) in the space of a couple of days, according to the Met Office.

The current reversal event in the Arctic began on March 4. However, the winds are starting to slow down, hinting that the vortex will return to its normal trajectory soon, Spaceweather.com reported.

"It was a substantial reversal," Amy Butler, a climate scientist at the National Oceanic and Atmospheric Administration (NOAA) and author of NOAA's new polar vortex blog, told Spaceweather.com. The speed of the reversed winds puts the event in the top six on record, she added.

Disruptions to the polar vortex can impact weather in the U.S., such as in 2019 when a massive cold front descended across the Midwest. These extreme weather events occur when the polar vortex deforms the jet stream — an air current that surrounds the polar vortex — exposing lower latitudes to large blobs of icy Arctic air.

This month's disruption did not change the shape of the jet stream, so weather patterns are expected to remain largely unaffected, according to Spaceweather.com.

However, the change in air temperature around the Arctic has sucked up large amounts of ozone from lower latitudes, creating a temporary ozone spike — the opposite of an ozone hole. Currently, there is more ozone surrounding the Arctic than at this time during any other year on record, according to Spaceweather.com. However, this ozone spike will disappear after the polar vortex returns to normal.

The current reversal is the second of its kind this year, following a smaller event in January that did cause a brief cold snap in some states, Butler wrote in NOAA's polar vortex blog.

Historical records show that SSW events are more likely to occur during El Niño or La Niña, the two contrasting phases of a natural cycle of planet-wide warming and cooling. During these phases, global weather systems become more unstable, which sets the stage for more frequent reversal events, Butler wrote in the NOAA blog.

We are currently in the midst of a major El Niño, which could make further reversals or disruptions more likely over the next year or so.

https://www.space.com/earth-polar-vortex-spinning-backwards-above-arctic-reversal-event

'Them space drugs cooked real good:' Varda Space just made an HIV medicine in Earth orbit

Mar 29, 2024

On Feb. 21, after some seven months in space, Varda Space Industries' W-1 capsule successfully returned to Earth, carrying with it a unique payload: the HIV/AIDS medication ritonavir.

Varda Space seeks to autonomously manufacture pharmaceuticals in microgravity, a strategy that could ultimately reduce the cost of life-saving drugs — and, according to a new preprint paper, the company is one step closer to achieving that goal.

The W-1 mission sought to test the feasibility of making therapeutics in space, testing Varda's hardware off Earth for the first time. During its time in orbit, the W-1 capsule successfully crystalized the metastable Form III of the antiviral drug ritonavir, which then survived its return to Earth. The space-processed ritonavir has since been analyzed, and per an X post by Varda Space cofounder Delian Asparouhov, "[t]hem space drugs cooked real good."

The mission's data, now published in the preprint paper, also provides crucial information about the effects of spaceflight and reentry — such as vibration, acceleration, radiation and temperature — on the pharmaceutical-production process.

"By providing a detailed experimental dataset centered on survivability, we pave the way for the future of in-space processing of medicines that enable the development of novel drug products on Earth and benefit long-duration human exploration initiatives," states the paper's abstract.

While pharmaceuticals have been processed in microgravity on parabolic flights and the International Space Station, Varda Space's method aims to be more efficient and cost-effective, using uncrewed capsules that serve dual purposes as a mini-factory and a reentry vehicle.

The company now hopes to inspire others to consider the viability of space-processed pharmaceuticals. "Together with our hypergravity platform, Varda’s rapidly advancing the landscape for drug development using microgravity," wrote Varda Space in a thread on X. "Our mission is to now enable cost-effective high-cadence access to enable next-generation therapeutics."

https://www.space.com/varda-space-microgravity-pharmaceutical-production-success