I’m puzzled as to why the planets, stars and moons are all round (when) other large and small objects such as asteroids and meteorites are irregular shapes?

— Lionel Young, age 74, Launceston, Tasmania

This is a fantastic question Lionel, and a really good observation!

When we look out at the Solar System, we see objects of all sizes — from tiny grains of dust, to giant planets and the Sun. A common theme among those objects is the big ones are (more or less) round, while the small ones are irregular. But why?

San Francisco is worried that highway 37 may be in danger of flooding. They invoke environmental justice, of course, but it's really about rich people going to their second homes in Napa's wine country on weekends. Rich people need peasants toiling to feel elite and without roads they can't get there.

Yet if San Francisco journalists and editors are concerned about rising water, why are they continuing to support dumping the water that poor people need into the Bay? It clearly does not need more water. Poor people who can't afford to live in Napa do.

During the COVID-19 pandemic, wealthier people had the money to stay home and order online. Not so for poor people, who instead made more trips to local dollar stores and small groceries to get their family's food.

Why is that bad? It isn't at face value, supporting local businesses is an aspirational claim for many, but a group of academics claim that without equal incomes and equal access to buying in bulk, poor people were worse off when it comes to making healthy food choices. That is like arguing muffin in a local bodega is bad while a muffin in a Whole Foods is good, when experts know the Whole Foods version has far more calories. 

With the delta variant of Covid-19 surging in many countries - e.g., over 100,000 new cases per day foreseen in the UK in the next few days, and many other countries following suit - we may feel depressed at the thought that this pandemic is going to stay with us for a lot longer than some originally foresaw.
In truth, if you could sort out your sources well, you would have predicted this a long time ago: epidemiologists had in fact foreseen that there would continue to be waves of contagions, although at some point mitigated by the vaccination campaigns. However, so much misinformation and falsehood on the topic has been since dumped on all media, and in particular on the internet, that it is easy to pick up wrong information.

Covid experts around the world respond to the UK’s decision to lift remaining restrictions on July 19 in an emergency online summit.

They say no public health officer would recognize this as a strategy.

This article as a tweet thread, including the short video clips of experts making their main points.

See::

An unknown methane-producing process is likely at work in the hidden ocean beneath the icy shell of Saturn's moon Enceladus, suggests a new study published in Nature Astronomy by scientists at the University of Arizona and Paris Sciences&Lettres University.

Adolescent girls and young women can and will use HIV prevention products with consistency, according to interim results of a study of two different methods: daily use of the antiretroviral (ARV) tablet Truvada® as oral pre-exposure prophylaxis (PrEP) and the monthly dapivirine vaginal ring, a new HIV prevention product currently under regulatory review in several countries.

To provide protection against HIV, both must be used consistently- daily, for oral PrEP, and for the ring, a full month at a time - which previous studies of these products found to be especially challenging for younger women.

In an observational study using data from the Veterans Health Administration for 2,344 U.S. veterans hospitalized with COVID-19, remdesivir treatment was associated with prolonged hospitalization but wasn't associated with improved survival. 

There is a belief that Airbnb listings cause increased crime in residential neighborhoods - or at least annoying late-night parties which increase risk of crimes. However, a new paper suggests that while Airbnb listings can be linked to a reduction in the local social dynamics that prevent crime, it isn't the tourists committing the crimes. And it takes years, which means Airbnb listings may be a symptom rather than the cause.

A new paper has statistically linked inflammatory bowel disease, an umbrella term for chronic inflammation of the digestive tract, to processed foods. But because every food is processed - no one eats wheat that hasn't been milled - the term has now become "ultra-processed."