@JohnBarentine@astrodon.social
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JohnBarentine

@JohnBarentine@astrodon.social

Astronomer. Historian. Author. Small business owner. Arizona native. Proud LGBT American. 🏳️‍🌈 Retiring to asteroid 14505. Questioning everything; occasionally getting in trouble for it. Toots about #Astronomy, #LightPollution, #DarkSkies, #Satellites, #SciencePolicy, #History and more.

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JohnBarentine, to random
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Artificial light is good and beneficial to humanity. But it's also possible to have too much of a good thing.

Follow the Five Principles for Responsible Outdoor Lighting: https://darksky.org/resources/guides-and-how-tos/lighting-principles/

JohnBarentine, to til
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that the American Enterprise Institute has built what looks to be a useful dashboard based on data aggregated by @planet4589 and @celestrak to visualize lots of information about trends in launches, and .

https://spacedata.aei.org/

JohnBarentine, to space
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Bad news for radio astronomy AND optical astronomy. Not only is 'Supplemental Coverage from Space' (aka direct-to-cell) transmission unregulated at this point, but the 2nd generation of satellites will be monstrously large reflectors of sunlight.

https://www.reuters.com/business/media-telecom/att-ast-spacemobile-tie-up-provide-space-based-broadband-network-2024-05-15

JohnBarentine, to sustainability
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Issued today. "There is a need for international coordination to foster transparency, clarity and consistency of relevant policies and regulations, ... to effectively address and promote the safety and of activities."

https://www.unportugal.ptspace.pt/wp-content/uploads/2024/05/Lisbon_Declaration_on_Outer_Space.pdf

JohnBarentine,
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@richard This declaration reads to me mainly as an affirmation of the existing process at COPUOS and doesn't really contain anything new. Maybe it's subtly pushing back on the Artemis Accords (as more countries sign them) as being too U.S.-centric. I'm not sure; I knew nothing about this conference or the declaration until it popped up earlier today on social media.

JohnBarentine,
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@richard As an outsider looking in at the COPUOS process in recent years, it's painfully slow (by design). It's a consensus body, and any one member State can hold up the proceedings (and States have done just that). It seems ill-suited to govern a realm where the pace of change in recent years has been lightning-fast. Yet every year COPUOS debates whether to continue even talking about these issues.

JohnBarentine,
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@richard Agreed. It seems sort of one-sided, which is why I mentioned Artemis. OST signatories have recently breached the treaty, indicating that they won't be bound by it any airtight manner. And I'm afraid that we're looking at outright acts of war in space sooner rather than later (and nothing can stop that now).

JohnBarentine,
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@richard 😅

JohnBarentine, to space
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"While there are still hurdles to overcome and challenges to solve before LSST can deliver on its extraordinary promises, thankfully, dealing with tiny bits of space junk likely won’t be one of them."

https://aasnova.org/2024/05/15/huge-survey-vs-tiny-space-junk/

(There's always a "yes, but".)

Yes, but: those tiny bits of debris contribute most to an expected rise in diffuse night sky brightness for ALL observatories.

See: https://academic.oup.com/mnrasl/article/504/1/L40/6188393

and:

https://www.aanda.org/10.1051/0004-6361/202037501

JohnBarentine,
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@silberspur That's a great question! The second paper I linked (by Bassa, Hainaut and Galadí-Enríquez) argues that intact satellites aren't the problem where diffuse night sky brightness is concerned. The smallest particles are the biggest contributor. If there were no small particles and only large satellites, the effect would be ~1% at most. But it could be considerably worse than 10% if, as Oli Hainaut said in presenting this work, the satellites"grind themselves into dust".

JohnBarentine, to Astronomy
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Today's H-alpha in good seeing conditions at 17:00 UTC.

There are not many days on which H-alpha views of the Sun include prominences that visualize the magnetic field lines above active regions particularly well, but today is definitely one of those days.

A pseudo-coronographic image of the limb of the Sun in the light of hydrogen alpha showing prominences extending above the solar limb in bright red hues. The solar disc is rendered artificially black. The prominence shown here curls around the magnetic field lines of an active region just beyond the solar limb, forming open and closed loops.

JohnBarentine, to space
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So, which is it?

"Musk's Starlink satellites disrupted by major solar storm" https://www.cnbc.com/amp/2024/05/11/musks-starlink-satellites-disrupted-by-major-solar-storm.html

or

"SpaceX Starlink satellites doing just fine after weekend solar storm, company says" https://www.space.com/spacex-starlink-solar-storm-healthy-satellites ?

It can't be both. 🤷🏼‍♂️

JohnBarentine,
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@reedmideke That's what I am trying to figure out. The company's communications make it sound like nothing is wrong at all, but its statement that "on-station" satellites are fine may be telling...

Also, it's unclear whether a distinction is being made between signal interruptions and possible damage to satellites.

JohnBarentine,
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@volkris It would be great if someone, either among the media or at the company, would clear that up.

JohnBarentine,
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@mimblewimble Evidently they didn't lose any objects in low parking orbits (unlike in 2022, which is good), but there were some service disruptions (which is not unexpected).

JohnBarentine, to random
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What's in a name? "While ‘artificial lighting’ may seem a fitting descriptor, it falls short in conveying the broader implications of human influence on night-time illumination."

https://journals.sagepub.com/doi/full/10.1177/14771535241244877

JohnBarentine, to Law
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New law review: "This Note argues that the existing tools in the Clean Water Act provide authority for the U.S. Environmental Protection Agency (EPA) to regulate light pollution and preserve the integrity of the nation’s waters."

https://scholarship.law.wm.edu/wmlr/vol65/iss6/6/

JohnBarentine,
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The review also argues that “regulation of light pollution does not trigger the Major Questions Doctrine following West Virginia v. EPA”.

This is the completely-made-up-by-SCOTUS doctrine that federal agencies shouldn't decide "major" policy questions. https://en.wikipedia.org/wiki/Major_questions_doctrine

JohnBarentine, to SpaceX
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Debris from the 26th February re-entry of a Dragon trunk has evidently been found on a farm in .

https://regina.ctvnews.ca/from-outer-space-sask-farmers-baffled-after-discovering-strange-wreckage-in-field-1.6880353

JohnBarentine, to random
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Today's H-alpha Sun in good seeing at 17:35 UTC. The timing is such that I watched an X-class develop over the span of about 15 minutes.

AR 3364/3368 is a real monster — easily one of the most impressive complexes of the maximum.

Detailed hydrogen-alpha view of a large solar active region and a feathery limb prominence beyond the limb at right. Only a small section of the solar surface is shown in shades of orange. The prominence is bright red.

JohnBarentine, to Astronomy
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A view of the today in hydrogen-alpha light under good seeing conditions. The combined complex of AR's 3664 and 3558 (below center) is a real monster with a complex 'beta-gamma-delta' magnetic field configuration. It has developed rapidly in the last 24 hours and is worth watching.

There was also a beautiful prominence on the Sun's southeast limb. Again, good seeing allowed for high magnification and the extraction of a lot of detail.

A pseudo-coronographic image of the limb of the Sun in the light of hydrogen alpha showing prominences extending above the solar limb in bright red hues.

JohnBarentine, to Astronomy
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"In general, space rocks larger than a kilometre can’t rotate more than once every 2.2 hours because they would break apart. But smaller like can withstand much faster spins because they are more compact."

https://www.newscientist.com/article/2428473-asteroid-that-broke-up-over-berlin-was-fastest-spinning-one-ever-seen/

JohnBarentine,
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@schnedan Apologies that I did not read your comment until now! I think you are correct that the bulk modulus of the asteroid (which in turn depends on its detailed composition) determines the critical spin frequency at which breakup would occur. Then again, we see relatively fast rotation speeds in, e.g., comet nuclei, which have almost no metal.

JohnBarentine, to Arizona
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"Preserving our dark skies provides economic opportunities, health benefits, reduces energy consumption, maintains cultural values and minimizes disruption to wildlife. It also has produced a thriving astro-tourism industry."

https://www.flagstaffbusinessnews.com/coconino-county-a-defender-of-the-dark/

JohnBarentine, to UnitedKingdom
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The U.K. All Party Parliamentary Group (APPG) for Dark Skies is hosting an in-person open meeting in London on Tuesday, 14th May.

Attendance is free; register on: https://www.eventbrite.co.uk/e/all-party-parliamentary-group-for-dark-skies-open-meeting-tickets-887599573217

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