Tag: astronomy

Measuring Dimensions

Credit SiBr4 – CC-BY-SA


We live on a rocky ball about 12,750 kilometers through and 40,050 kilometers around its widest diameter. It has a mass of about six quadrillion megatonnes, which is so ridiculously large compared to things we’re used to that it doesn’t really mean anything to us. Our size compared to Earth’s size is roughly equivalent to the size of viruses compared to us.

That is not to imply that humans are like germs living on Earth. It just provides some perspective on where we are. To go a little further, the next level at the same ratio compares the size of the planet Earth to the size of the whole Solar System. Give or take a few billion kilometers. It’s not an analogy that can stretch forever. (Here’s a link to a video that goes from the very small to the very large – 10 minutes)

And it doesn’t imply that humans are merely an unimportant example of a repeating theme. After all, why is our size one of the levels? We could just as easily be included with all of life to fall between the very small and the very large. As in – subatomic particles – living things – planets and stars. But that’s another analogy that shouldn’t be pushed too hard.

We choose humans as a level because we’re human. We tend to look at things relative to what we’re used to, so we don’t think twice about our size being one of the steps on the ladder. Besides, it was necessary to use something familiar as a point of reference in such a wide array of dimensions.

The dimensions of the physical universe are measured by such huge numbers, both hugely big and hugely small, that they don’t convey much meaning on their own. The very large is measured in billions of light years. Light years are trillions of kilometers each. Even a single kilometer is big compared to us. The small is measured in fractions of meters, changing the numbers from positive to negative right about our size. The very smallest things are such small decimals of a meter that we don’t write them out in full, using special mathematical shorthand instead.

In all that vastness, all that range of realities and possibilities, what is most amazing is that part of it is conscious. A narrow band in the middle has produced something that can look out and try to understand the whole thing.

I think we can justify being a little self-centered.

Help for Hobbyists


I’ve just learned of a website dedicated to hobbies — HobbyHelp. They describe themselves as, “a small team of enthusiasts, looking to share our knowledge and experience with anyone looking to start a new hobby.” Some of the most popular posts are, 10 Most Popular Hobbies in the World, 10 Hobbies That Look Great on Your Resume, and The Ultimate Beginner’s Guide to Astrophotography. But what brought me to the site was a message from Jenny, one of the bloggers at HobbyHelp. She had seen my post, NASA Image and Video Library, about NASA’s consolidation of its scattered resources into a single archive, and reached out to me with a link to a post of hers, The Ultimate Beginner’s Guide to Astronomy.

I think HobbyHelp is selling itself short by limiting its audience to beginners “looking to start a new hobby.” I think their site would be useful to people who are already involved in a hobby, too. People who are trying to expand their knowledge, or who are contemplating taking the next step in their experience. That is certainly true of Jenny’s post mentioned above. The depth of her research is plain to see. The care in the writing is obvious. While useful to someone taking their first steps in the hobby of astronomy, her piece would also be useful to people further along.

If you’re looking for a new hobby, visit the HobbyHelp website. If you’re interested in astronomy, visit Jenny’s post. Either way I think you’ll be rewarded for your effort.

rjb

August 5, 2019

I got a note from Charles Wade of the NightSkyPix website asking if I would like to add a link to his site to offer my readers an additional source of information. From the site:

NightSkyPix is dedicated to learning and teaching all aspects of astrophotography and night-time imagery.

I had a look at the site and could see no obvious reason why I shouldn’t link to it. It looks like a thorough and professionally-crafted site dedicated to astrophotography.

Charles Wade – NightSkyPix

So, there it is.

rjb

Alfred Wegener

Alfred Lothar Wegener was born in Berlin, Germany on November 1st, 1880. He was the youngest of the five children of Richard Wegener, clergyman, theologian and classical language teacher. The family was well-off enough to own a vacation home, as well as to afford to educate all their children. Alfred did very well in school and went on to study physics, meteorology and astronomy. He got a doctorate in astronomy in 1905, but had formed a strong interest in the growing disciplines of climatology and meteorology.

Public Domain

Wegener made four expeditions to Greenland in his study of the polar climate, the first in 1906. He built a weather station and made observations using kites and tethered balloons, in addition to the usual instruments. He had his first experience with the killing harshness of Greenland’s climate when the expedition leader and two others died while exploring. He returned to Germany in 1908.

His second expedition to Greenland in 1913 began with a calving glacier that almost wiped it out, and ended with a fortunate and unlikely rescue as their crossing of the interior resulted in their having to eat all of their dogs and ponies before its completion.

His military service in World War One lasted only a few months. He faced fierce fighting, was injured twice and declared unfit for duty. He spent the rest of the war in the meteorological service and published 20 papers by its end. Having published on his ideas about continental drift for the first time in 1912, Wegener followed up with a major work — “The Origin of Continents and Oceans” — in 1915. Interest was small.

After the war he worked as a climatologist and as senior lecturer at the University of Hamburg. In collaboration with Milutin Milankovich, he did pioneering work in a field that would become known as paleoclimatology, where they reconstructed ancient climates. He published the third edition of “The Origin of Continents and Oceans,” provoking discussion of his theory of continental drift, and disparagement by the experts of the day.

By 1924 he attained a position that provided stability for his family, and he was able to concentrate on his studies for the rest of the decade. In 1926 he presented his ideas on continental drift at a symposium in New York, to near-uniform rejection. In 1929 he published the fourth and final edition of “The Origin of Continents and Oceans,” and made his third expedition to Greenland.

Wegener led the 1930 Greenland expedition, his fourth, and his sense of personal responsibility ultimately led to his death. A combination of a late thaw and harsh conditions resulted in the failure of a re-supply mission and the death of Alfred Wegener. His body remains buried where he died.

Public Domain

Alfred Wegener was accomplished at astronomy, meteorology and climatology, but what he is known for today is continental drift. We’ll cover that in more detail in future posts.

rjb

It’s Never Aliens

UFO-self-made-Meersburg-Stefan-Xp-cc-by-sa-640

Credit Stefan Xp – CC-BY-SA – Self-made UFO over Meersburg

It was a good year for aliens. Whether it was the fluctuations in the brightness of Tabby’s star, the oddly shaped interstellar visitor that passed through the Solar System, or a spate of sightings of UFOs, aliens received a lot of nominations. As always with the advocates of alien visitations, they want us to prove that it isn’t aliens. They say, “How do you know it isn’t? Can you prove it isn’t?” They always get that backwards, don’t they?

From the Scientific American article:

What do a strangely fading faraway star, an oddly shaped interstellar interloper in the solar system and a curious spate of UFO sightings by members of the U.S. military all have in common?

Far from being close-minded killjoys, most scientists in the “never aliens” camp desperately want to be convinced otherwise. Their default skeptical stance is a prophylactic against the wiles of wishful thinking …

Finding aliens—or coming up empty in our searches—has profound implications for our own ultimate cosmic fate.

UFO detections have remained marginal for decades; they’ve just gone from being blurry shapes on film cameras to blurry shapes on the digital infrared sensors of fighter jet gun cameras. This, in spite of the fact that the world’s total imaging capacity has expanded by several orders of magnitude in the past 20 years.

Hypothetical aliens with advanced technology could do that, of course. But then you have to ask why they would choose to remain marginally undetectable rather than just being undetectable.

Read the original article at Scientific American.

via It’s Never Aliens–until It Is – Scientific American

It was a good year for alien hunters, but not good enough. They still haven’t come up with solid proof that their beliefs are true. I guess that’s why they keep asking us to prove that they aren’t, even though that’s the wrong way ’round.

rjb

NASA Image and Video Library

You might be aware of the website dedicated to the Astronomy Picture of the Day (APOD.) You can visit the site and see another great picture every day. Some people even set things up so their computer’s desktop image is the APOD changing daily. It’s a NASA website and just one of the ways that organization shares its discoveries with the public. Today I’m going to direct you to another one called the NASA Image and Video Library. They have brought together about sixty of their media archives into one source. Here’s an article on Space.com about the library.

Here are some samples of the images available. They link to the much larger originals. These images are Public Domain.

Let’s start with a spacewalk.

Next the aurora on Jupiter.

The mystery of Saturn.

Here’s one you might recognize: the Helix nebula.

Finally, a bit of space dust.

Happy rummaging.

rjb

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