We've all been there before. Someone asks a question about a topic we're presenting on, and we're not quite sure how to answer. Maybe we're completely stumped. Maybe we only half-remember the subject. We don't want to disappoint the audience or leave them hanging, but we don't want to say something totally wrong. What do we do?

Indeed, it's exactly that situation that prevents a lot of people, especially scientists, from engaging in public outreach. For a scientist, being correct and thorough is a key part of any communication, from an email to a conference presentation. We train for weeks on a talk, preparing ourselves for any potential question. But with the general public you never know what you're going to get...so you're better off not even trying.

Just putting yourself out there in front of an audience is a major achievement.

Mistakes are going to be made. Wrong numbers will be quoted. A simplification of a topic will leave an important aspect out. Words will get flipped around. That's life, and that's fine, as long as we're constantly challenging ourselves to do better. It's okay to say "I don't know." It's okay to admit a mistake. It's okay to go back over a topic.

Sometimes science communication requires a little risk.

Maybe you've reached your limits on turkey sandwiches, and perhaps that stuffing is looking a little long in the tooth. But your leftovers are far older than you might think:

- Turkey is a great source of selenium, an essential nutrient. This element was forged in a supernova explosion billions of years ago, maybe even just before the formation of the solar system.

- Cranberries have lots of fiber, which is just carbon. Carbon is fused inside stars like our sun near the end of their lives.

- Your stainless steel silverware is mostly made of iron, which is only formed in the most massive stars just before they detonate as supernovas.

- Your beverage of choice contains a lot of water, the most common molecule in the universe. The oxygen comes from sun-like stars, and hydrogen is the oldest element of all, coalescing in the first 20 minutes of the big bang itself, over 13.8 billion years ago.

So maybe it's time to toss those leftovers.

With the dinosaurs finally here, and all the excitement and interest they bring, it's important to remember what really matters this holiday season: giant meteors falling from the sky.

Some paleontologists had long suspected that an impact may have spelled the end of the dinos, because their demise came so swiftly (geologically speaking). Some estimates suggested it took as little as 10,000 years to wipe them from the face of the Earth. It's so striking: we have rock formations that are infested with dinosaur bones below a certain line, and above it they're simply gone.

Another striking feature prompted a team led by physicist Luis Alvarez and his son, geophysicist Walter Alvarez, to propose the impact as a hypothesis in the early 1980's. Their reasoning came from iridium, which is rather rare in the Earth's crust, but is found in abundance in a thin layer separating dinosaur from not-dinosaur rocks. It's also found in asteroids.

Around the same time, but unknown to them, geophysicists working for the Pemex oil company discovered the half-submerged remnants of, you guessed it, a giant impact crater centered on the town of Chicxulub, Mexico. The crater is over a hundred miles wide and ten deep, and dates to the same age as the extinction event.

While other sources like the volcanic Deccan Traps and changing sea levels were causing stress on our dinosaur friends, and likely contributed to their downfall, there's little doubt that a 10 kilometer wide rock from space did some serious damage.