What’s In It for Humanity?

We’re getting a lot of commentary these days about future missions to the Moon. Some people want us to go back there, others want to go straight to Mars or an asteroid, or some other place (like a lunar space station). It’s all do-able since we were able to send people once. We should be able to do it again. The big questions are: when we will do it? And who’s “we”? And what will we do first? That’s all TBD, and of course, politics and funding will play a role in the answers.

As part of an exhibition project, a group of us were discussing the future of solar system exploration. One scenario we talked about was using the Moon as a research base and training ground for missions to other places. The rationale is that the Moon is close enough that if something goes wrong while people are living and working there that a rescue could be attempted from Earth. Of course, missions to the Moon aren’t so habitual yet that just mounting up a quickie hop to save some lunar colonists isn’t going to be easy. At least, not yet. But, exploration of the Moon does offer some attractive advantages.

The Lunar Advantage

As a research base, the Moon has a lot going for it. It is also a fine jumping-off spot to mount expeditions to other places. And, a place to train for living in low-gravity environments, along with whatever orbital assets the world has in place (such as ISS or a lunar gateway module). Granted, the Moon’s a bit more environmentally extreme than Mars, for example, but it’s still a good next step toward learning to live and work on other worlds.

Mars Bound?

Another idea was to just go to Earth orbit, build some ships, and leave for Mars. As a quickie approach, it has a lot of attractiveness. BUT, how do you get the pieces and parts up to orbit for the ship to be built? Out of Earth’s gravity well? Isn’t that going to be costly? Yes, of course, we did that for ISS, but that was then. This is the future. Costs are still costs and it’s not cheap to heave stuff up from Earth, much less heave astronauts/space construction crews to put it all together. That’s true no matter which scenario that ends up happening. But, heading to Mars is going to be a lot more complex than we expect, and probably pose many more hazards to the people who make the trip.

Living and working on another world is where a lunar base comes in handy, as well as an asteroid mining expedition. Theoretically, you could mine the stuff of ships from those two places, create your ships in lunar orbit, and then head out to Mars (or wherever) from there. That isn’t what the “Get Your Butt to Mars” folks want to hear, but it may be more feasible in the long run.

What Will It Be?

From the vantage point of today, I am not so sure what scenario will happen. I know what we liked for our exhibit plan. However, reality has a different way of unfolding than a relatively simple exhibit. In the meantime, in reality, we have China doing its thing on the Moon, we have NASA planning all kinds of things for the Moon and then Mars, and there are people in Luxembourg and elsewhere who want to go straight to asteroid mining (and not necessarily to get materials to build spaceships).

It’s a much more complex future for the Moon and Mars than we can imagine right now. And, that’s not all bad. Eventually, people will get to the Moon, set up research stations, colonies, etc. And, they’ll get to Mars, for the same reasons. The human exploration of the solar system will happen. Like anything else, though, it’s not going to go according to plan. It’ll be interesting, surprising, and probably incredibly difficult!

Hubble Spots an Ancient Galaxy Near Us

So what was the early universe like? What were the early stars like? What about infant galaxies? It seems that the Hubble Space Telescope may have uncovered an object to help answer those questions. It was doing an observation of a globular cluster called NGC 6752. The cluster of stars is actually part of our Milky Way galaxy. It lies about 13,000 light-years away from us, in the direction of the constellation of Pavo. This tightly packed cluster contains well over a hundred thousand stars. The core of the cluster is a region about 1.3 light-years across and overcrowded with stars. This cluster is visible to the naked eye from a dark sky sight.

In the course of the observation, the telescope found another population of stars that’s somewhat hidden behind NGC 6752. This collection of stars is actually a “dwarf spheroidal” galaxy, called Bedin 1. The image shows this dim little dwarf (circled) in the lower left. The bright stars of the globular outshine Bedin 1 by quite a bit.

Why Isn’t Bedin 1 a Cluster?

So, one question about Bedin 1 is whether it’s really just another cluster of stars like the nearby globular. As I looked at the image, I thought about the difference between a globular cluster and a dwarf spheroidal. It turns out that the delineation between them isn’t always clear. Both types of objects have stars that are very old, and very often metal-poor. That last bit is important because the very youngest stars in the universe were also metal-poor. Not until the first generations of stars were born, lived their lives, and died did the universe become enriched with elements heavier than hydrogen and helium.

That’s because as stars live, they produce elements heavier than hydrogen and helium in their cores. At their deaths, those elements: carbon, nitrogen, oxygen, and so on, are spread out to surrounding space. The most massive stars are also implicated in the creation of such elements as iron, gold, and so on. Neutron stars are also involved in the creation of heavy elements when they collide with each other.

I mentioned that globular cluster stars are also very old. And, they, too, are often metal-poor. So, what’s the difference between a dwarf spheroidal and a globular? It turns out there’s more than metallicity to worry about. To figure out which one is a dwarf spheroidal and which is a cluster, astronomers have to study the motions of stars in both types of objects. Motions are affected by mass, and it turns out that we have to look at the amount of dark matter involved. A dwarf spheroidal is likely to have more dark matter, and hence, more mass, than a globular cluster.

What Does Bedin 1 Tell Us?

That brings me back to Bedin 1. It’s likely to be a dwarf spheroidal if it’s massive (meaning it has a large component of dark matter for its tiny size: only 3,000 light-years across. It’s also very dim. Of course, astronomers will continue to study and measure its mass.

So, what this means is: galaxies in the early universe were relatively metal-poor. And, dwarf spheroidals like Bedin 1 represent that early, “pristine” universe. The coolest thing about Bedin 1 is that it’s a remnant of that very early universe. Its stars hark back to a time when the universe was very young. And, it shows us what stars were like at that time.

Luckily, Bedin 1 hasn’t had a history of collisions with other galaxies. It has existed since early times as much as it is today. And, that gives astronomers a great look back in time to the infancy of the cosmos. It reveals what galaxies might have been like at a very young age. That was before the explosions of stars enriched them with elements that ultimately led to planets and life.