One of the interesting aspects of science is the fact that what we observe is often not what we measure. The data gathered from a particular experiment is just one aspect of scientific study. To really make progress you need to put that data within the context of scientific models. As a result, most of what we study in astronomy and other sciences is deeply dependent upon the models we use to understand the universe.
Blink of an Eye
One of the aspects of astronomy that’s hard to wrap your head around is the immense time scales of the heavens. We measure the lifetimes of stars in billions of years, while the light from the nearest galaxies takes millions of years to reach us. Human civilization, on the other hand, is measured in thousands, and a human lifetime tens. …
A Galaxy Far, Far Away
A while back in Nature a paper was published on the most distant confirmed galaxy discovered so far. The paper is behind a paywall, but you can see the arxiv version here. The galaxy, known as z8 GND 5296 has a measured redshift of 7.51. You can see the galaxy in the image above. So just how far away is this galaxy? It depends on which distance you are talking about.
Raising a Glass
Glass has the useful feature of being transparent at optical wavelengths. That, and the fact that light can refract (change direction) when it passes through curved glass is what made it useful as lenses, and eventually telescopes.
Missed Connections
Typically in astronomy we award credit of discovery to whomever identifies an object and recognizes what it is (or at least recognizes it’s something strange). But once the dust has settled, we can sometimes look back on earlier observations and find that someone else saw it first, but didn’t recognize its importance. If we gave credit to the first observer, some astronomical history would be very different.
Foreshadowing
If you happen to catch this eclipse and are waiting for a total one, you won’t have to wait too long. Make plans for August 21, 2017. On that day a total eclipse will cross the US from Oregon to South Carolina, making it within a day’s drive of most of the country.
National Geographic Effect
You can see this effect in the image above. On the left is a Voyager II image of Jupiter’s great red spot as it appeared in NatGeo and elsewhere. On the right is the same image in its more true-color form. You can see why the colors were boosted. The true-color image lacks much of the depth and richness we like to see in images.
Sticks and Stones
We typically think of telescopes as the tools of astronomy. While they are central to modern astronomy, telescopes are a relatively modern tool. We typically consider Galileo as the founder of telescopic astronomy in the early 1600s, but observational astronomy has a much longer history.
More Echoes
With the discussion of light echoes today, here’s another interesting one. In 2002 the star v838 Monocerotis swiftly brightened to about a million times the brightness of the Sun before dimming down again. This burst of light then traveled outward from the star, illuminating the gas and dust surrounding the star. Because the light burst was relatively short, this meant that successive layers of the gas and dust were illuminated as the sphere of light expanded.