Universe Today Podcast

How old is the Universe? In order to figure that out, all you have to do is figure out how quickly it’s expanding, and then the clock backward until everything is crunched together.

And astronomers have measured the rate that the Universe is expanding with tremendous precision at various times in its history; at the beginning, and much more recently. The problem is, these expansion rates disagree, but they’ve both been measured so accurately that their error bars don’t overlap.

In other words, there are multiple, highly accurate estimates for the age of the Universe, and they disagree.

In this week's questions show, I explain why I don't think we always need to be realistic, if galaxies in the local group are bound together gravitationally, and what we should call Earth-moving equipment on Mars.

Extending humanity to other worlds in the Solar System is at the very limits of our modern technology. And unless there are dramatic discoveries in new propulsion systems or we learn how to build everything out of carbon nanotubes, the future of space exploration is going to require living off the land.

The technique is known as In-Situ Resource Utilization or ISRU, and it means supplying as much of your mission from local resources as possible.

And many of our future exploration destinations, like Mars, have a lot to work with. Let’s look at the raw materials on Mars that missions can use to live off the land and the techniques and technologies that will need to be developed to make this possible.

In this week's questions show, I explain why you could have a steam-powered rocket, how often spacecraft have crashed into asteroids and comets, and why a red supergiant star actually has a very low surface gravity.

The exploration of Venus has been mainly about getting down to the surface of the planet. The Soviet Union sacrificed lander after lander to discover just how extreme the conditions are down there on the ground.

But higher up, among the clouds, the climate on Venus is surprisingly Earthlike in temperature and pressure, and there have been some fascinating ideas for robotic and human explorers to fly the skies of Venus, to help understand our evil twin planet.

Let’s take a look at them.

This week I'm joined by Jason Derleth from NASA's Innovative Advanced Concepts (or NIAC). This is a special part of NASA that funds innovative ideas for new telescopes, propulsion systems and rovers. Many of the cool, science-fiction ideas I present on this channel come from research done at NASA.

In this week's questions show, I explain why we can see meteor showers every year, why we're not 3D printing telescopes in space, why there aren't any plans to launch telescopes with SpaceX Starship. And a lengthy answer to one of the most common James Webb questions we get: can it be refueled? This was answered by Paul Geithner, a Deputy Project Manager for James Webb during a recent livestream.

In case you're interested, I was the special guest rogue for episode 750 of the Skeptic's Guide to the Universe. This long-running science podcast features all kinds of topics relating to science and skepticism. We talked about recent news in space and astronomy as well as the pseudoscience that I run across in my job. If you haven't already, you should definitely subscribe to their podcast, it's one of my favorites.

https://www.theskepticsguide.org/

We talked about the implications of SpaceX Starship, Starlink, why power beamed from space or asteroid mining will never turn a profit down here on Earth, and why he's not that scared about space radiation.

When it comes to telescopes, bigger is better. That’s true down here on Earth, and it’s especially true out in space. As astronomers and engineers design the next generation of giant space telescopes, they’re running up against the limits of current launch providers. There are only so many ways you can fold a huge telescope to get it to fit inside a 5-meter launch fairing.

The upcoming James Webb Space Telescope is pretty much the very limit of what you can construct on Earth and put into space in a single launch. To go bigger, space agencies will need to consider assembling their next-generation space telescopes… in space.