"Welcome to Pittsburgh Backyard and Garden. Today, we're tackling a common garden pest, the strangle vine." Hal Rogers grinned at Jane Kryskill's camera and motioned for her to pan right with the slightest tilt of his pith helmet.

"No way in hell," Jane murmured. She did not need five years experience of filming in Pittsburgh to know that a half-eaten deer did not make good ratings. It might be sensational news on Earth. It was, however, a fairly typical outcome when an Earth animal met any number of Elfhome carnivorous plants. Eighty percent of their Pittsburgh viewers would not be impressed, and the other twenty would call the studio the next day, pissed off that their dinner had been ruined by the sight.

Hal's grin tightened slightly as he continued. "The strangle vine is a dangerous plant to deal with as it’s a master of disguise. It can produce up to five different types of foliage, depending on the type of anchor it attaches itself to. It makes safely identifying this plant very tricky. Thus, it's best to investigate any possible outbreak with weapon in hand. Some people like a machete. Others: an axe. Personally, I like a flamethrower."

Ferrara, 1523 AD

This was going to be difficult. There really wasn’t any easy way into the walled city of Ferrara, or, now that it was too late, even a chance to get out of the queue to enter the Porta di Leoni. All that young Antimo Bartelozzi could do was be his normal assassin self – in other words, try to be invisible, or at least un-noticed. It didn’t help that eight out of every ten people heading through the crenellated city gate were female, and the gate-guards were searching and questioning all the males. Antimo could do a good job of passing for a woman. It did cause complications when the soldiers tried to get his skirts up and rape him, though.

That was too common a problem here in the fractured and squabbling city-states of Italy to make that disguise worthwhile, in general. Antimo’s task was to kill the ruler of this city, not to stab its soldiery. Of the various tasks his master had sent him to do, it looked likely to be the hardest yet. And he had a bare five weeks to return. Part of the time he had been given was lost to travel and preparation. He had four weeks and five days, now.

It was something of an unsavoury challenge, but he did what he had to do.

Figure 1. Shown are the galaxies making up galaxy cluster 1E 0657-66. On either side of the center, the pink clumps show hot gas detected by NASA’s Chandra x-ray observatory. Just outside this gas are regions where the bulk of the matter resides (shown in blue). This matter, detected via gravitational lensing, shows where the Dark Matter that makes up most of the mass of the cluster lies.
(Image courtesy of NASA.)

In the ‘eye’ of a hurricane, the sea level rises precipitously. Your ears ‘pop’ as you rapidly rise in the elevator to the top of the Empire State Building in New York City. Air pressure.

The compass needle spins and settles pointing north – an unseen force acts to align the iron-containing needle in a northerly direction no matter where you are in the northern hemisphere. Magnetism.

The water runs down the hillside toward the pond below. The Earth flies through space at about 67,000 miles per hour tracing a circular path around the Sun and doesn’t fly off into deep space. Gravity.

Two pieces of uranium are brought together under controlled conditions and they begin to grow warm and give off heat. They are brought rapidly together in a unique geometry and they explode, producing a ‘nuclear’ explosion. Radiation.

The velocities of stars orbiting the centers of galaxies, rather than decreasing as a function of distance as would the velocities of planets orbiting a star, remain constant out to the edge of the galaxy. Gravity bends space-time, causing light to focus when it passes by a massive object, allowing scientists to measure of the mass of the object bending the light in a process called Gravitation Lensing; The bending of light is much, much larger around celestial objects than expected. Dark Matter.