# ‘Event Horizon’ Star Sam Neill’s Perfect Response to Black Hole Photo

While many downplayed the event on social media yesterday, we now have our first ever look at a black hole. It’s been mathematically theorized for decades, but we now have visual proof of one’s existence, and that’s a pretty fucking big deal. Unless of course, you were on the Lewis and Clark.

Event Horizon actor Sam Neill took to social media with this hilarious tweet:

Been there, done it . #EventHorizon #BlackHole https://t.co/AKp8no6HTd

— Sam Neill (@TwoPaddocks) April 10, 2019

As many of you know, Neill’s Event Horizon character Dr. William Weir was one of the many passengers on the Lewis and Clark, a rescue ship sent to investigate a ship that once disappeared into a black hole only to return. Spoilers from 1997, but the Event Horizon went to Hell before returning to our dimension.

Let’s just hope that we don’t go anywhere near this black hole…

# Watch: Interview With Ebbe Altberg on the Future of Second Life & Sansar

Update, 4/5: Bumped up for weekend viewing and discussion! Here’s my near hour-long chat with Linden Lab CEO Ebbe Altberg during GDC week in March, a fascinating and wide-ranging conversation we had at Linden’s HQ in San Francisco. Related to…

# Turán’s Brick Factory Problem

During World War II, Hungarian mathematician Pál Turán was forced to work in a brick factory. His job was to push a wagonload of bricks along a track from a kiln to storage site. The factory contained several kilns and storage sites, with tracks criss-crossing the floor among them. Turán found it difficult to push the wagon across a track crossing, and in his mind he began to consider how the factory might be redesigned to minimize these crossings.

After the war, Turán mentioned the problem in talks in Poland, and mathematicians Kazimierz Zarankiewicz and Kazimierz Urbanik both took it up. They showed that it’s always possible to complete the layout as shown above, with the kilns along one axis and the storage sites along the other, each group arranged as evenly as possible around the origin, with the tracks running as straight lines between each possible pair. The number of crossings, then, is

$displaystyle mathrm{cr}left ( K_{m,n} right ) leq left lfloor frac{n}{2} right rfloor left lfloor frac{n-1}{2} right rfloor left lfloor frac{m}{2} right rfloor left lfloor frac{m-1}{2} right rfloor ,$

where m and n are the number of kilns and storage sites and $displaystyle left lfloor right rfloor$ denotes the floor function, which just means that we take the greatest integer less than the value in brackets. In the case of 4 kilns and 7 storage sites, that gives us

$displaystyle left lfloor frac{7}{2} right rfloor left lfloor frac{7-1}{2} right rfloor left lfloor frac{4}{2} right rfloor left lfloor frac{4-1}{2} right rfloor = 18 ,$

which is the number of crossings in the diagram above.

Is that the best we can do? No one knows. Zarankiewicz and Urbanik thought that their formula gave the fewest possible crossings, but their proof was found to be erroneous 11 years later. Whether a factory can be designed whose layout contains fewer crossings remains an open problem.