The Artemis II astronauts are settling back into life on Earth, but we’re not quite tired yet of hearing about their amazing journey. There’s a new PBS documentary now streaming on YouTube that dives into the Artemis program and the latest efforts to send humans to the moon again. Also this week, NASA shared some awesome images of a comet flying into the sun, the nonprofit American Rivers released its annual report on the most endangered rivers in the US and ESA posted a throwback image of Mars to highlight some interesting changes down on the surface. Here are the science stories that caught our attention this week.

A comet grazes too close to the sun

Earlier this month, a recently discovered comet made a close approach to the sun — but it couldn’t handle the heat. NASA has shared incredible images of the encounter that took place on April 4, showing the comet exploding into dust as it swings around our star. As NASA notes in a social media post, this was “its first and last observed flyby of the Sun.”

The comet, C/2026 A1 (also known as MAPS) was first spotted on January 13 of this year. As it neared the sun, it was observed by a slew of instruments: NASA and ESA’s SOHO (Solar and Heliospheric Observatory) spacecraft, NASA’s STEREO (Solar Terrestrial Relations Observatory) and NASA’s PUNCH (Polarimeter to Unify the Corona and Heliosphere) mission. This allowed for views of its passage from multiple angles. Seen in a narrow-field coronagraph view captured by SOHO, the comet appears to plunge directly into the sun. But, the wide view from NASA’s STEREO shows it actually swinging closely around the sun before breaking apart.

MAPS was one of a family of comets aptly called Kreutz sungrazing comets, and according to Karl Battams, the principal investigator for SOHO’s coronagraph, its destruction occurred likely several hours before what would have been its closest approach.

Potomac named most endangered river in the US

The nonprofit conservation organization American Rivers has released its 2026 report on the most endangered rivers in the country, and data centers play a major role in the status of its top pick. According to American Rivers, the Potomac River is the most endangered in the US due both to the threat of sewage pollution from aging pipe systems and the “unprecedented surge in data center development” in its vicinity.

The Potomac River basin spans parts of Pennsylvania, Maryland, Virginia, West Virginia and Washington, DC. In January, the catastrophic failure of the Potomac Interceptor wastewater pipe in Montgomery County, Maryland dumped hundreds of millions of gallons of untreated sewage into the Potomac River and the Chesapeake and Ohio (C&O) Canal, causing bacteria levels to hit over 4,000 times the safe recreational limit at sites closest to the incident, according to the report. The Potomac Interceptor is over 60 years old, and is just one of many in the region that is at or past the 50-year service life, American Rivers notes.

On top of that, data center development in places like Virginia and Maryland has skyrocketed, which could put a strain on local water and energy sources. Data centers also have potential to cause further pollution to the river.

“The region currently has over 300 data centers and is on track to have a total of about 1,000 centers occupying roughly 200 million square feet of buildings — enough to cover 3,472 football fields — on an estimated 20,000 acres of land,” the report explains. “These facilities pose a significant and growing threat to both water quality and water quantity, yet are being approved without meaningful transparency, regulatory review, and assessment of cumulative impacts.”

The organization is calling for Congress to reauthorize infrastructure funding bills so aging systems can be upgraded, and for regulators in these states to require transparency about data centers’ resource use, along with comprehensive environmental assessments before development plans are approved.

Mars ash: then vs now

The European Space Agency this week shared a look at how a region on Mars has changed since it was observed by NASA’s Viking orbiters way back in 1976. New images captured by ESA’s Mars Express spacecraft show how dark volcanic ash has encroached upon a swath of land in an area known as the Utopia Planitia basin. If you visit the blog post, you’ll find a side by side comparison of images from the two time periods.

It’s a rare example of an observable change on the surface of the red planet that’s occurred over such a short period of time, ESA notes. The agency explains, “The spread of the ash over the last 50 years has two possible explanations: either it has been picked up and moved about by martian winds, or the ochre dust that previously covered the dark ash has been blown away.”

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