Astronomy Object of the Week - No.5

It's been a while since the last Astro Object of the Week, but here it is! This'll be a little introduction to the variable star SS Cygni, located in the constellation Cygnus, the Swan.

First things first: SS Cygni is categorized as a lot of different things, including a cataclysmic variable star, U Geminorum type dwarf star, and dwarf nova. As a cataclysmic variable star, it will eventually trigger a Type Ia supernova. SS Cygni is a binary system consisting of a white dwarf and a red dwarf that are so close together that one revolutionary period is only a little over six and a half hours long.

Throughout its rotations, the white dwarf will accrete matter from its companion, a common characteristic of dwarf novas. These white dwarfs are also involved in periodic outbursts in which the luminosity will increases due to instability in the accretion disk, every seven to eight weeks in this case.

When the mass of the white dwarf is close enough to or over the Chandrasekhar limit (1.4 solar masses), runaway carbon fusion will occur and lead to a spectacular (yet morbid) display of colors.

The Marsupials of Australia

Good day, mates! It's been a week since I got back from my trip Down Under and visited the Australian cities of Sydney, Melbourne, and Gold Coast and the New Zealand cities of Queenstown (South Island) and Auckland (North Island).

It was a wonderful trip in general, but one of my favourite places on my journey was probably the Gold Coast. Here, I got to visit the Currumbin Wildlife Sanctuary, where I met some of the cutest and most amazing animals in the world, including koalas and kangaroos. The collection of species at the sanctuary reflected the fauna of Australia as a whole and therefore a large number of marsupial mammals, which I'll be talking about today.

Marsupials are interesting as mammals since they only occur in the Americas and Australasia (Australia, New Zealand, New Guinea), and 70% of those 334 extant species are endemic to Australia. Some of the most widely known Australian marsupials are koalas, kangaroos, wallabies, wombats, possums, and Tasmanian devils. Placental mammals are very rare in Australia, and the dingo, another famous Australian animal, is not actually a native species.

 

The most iconic characteristic of marsupial species is that the young are carried in a pouch after birth. There are also differences in other anatomical structures, including the brain; the marsupial brain does not have a corpus callosum that connects the brain hemispheres as Eutherians do. The skull and skeleton are also different.

However, perhaps the most marked difference is definitely in the reproductive system, in both structure and gestation process. Pregnancy is very short, and the embryo is born in an early stage of reproduction, reducing the risks of long-term pregnancies. This newborn joey finds its way to its mother's pouch and latches onto one of the many nipples there, from which it will receive food and develop more fully to one day be able to live out of the pouch.

Now here are some cute marsupials for your viewing enjoyment!

Harvard's Natural History Museum

I've done the Fossils event and currently am doing the Rocks and Minerals even for Science Olympiad. As a (self-proclaimed) expert on these topics, I've visited several natural history museums, including the LA Natural History Museum, which is absolutely incredible, and the London Natural History Museum, which is stunning. But I have to say that, for its size and collection, Harvard University's Natural History Museum is surprisingly wonderful.

The array of specimens at Harvard is amazing for a place less than half the size of the LA or London museums. Every single rock or mineral specimen, every single fossil that I had to know (and more!); Harvard had it all. And not only were the specimens present, but they were also in top condition. There is, of course, also the world's only exhibit of realistic glass flowers.

This last time I went, just about a week ago, I was still awed by everything that I had seen on a previous trip. It's definitely a place that everyone, especially if you're interested in geology, should take a trip to.

Paint With All the Colors of the Rainbow

Joyeux quatorze juillet to anyone in France or who loves French culture (like me)! I'm not going to post Nematodes (Part II) quite yet.

So, I just started reading a book called Schrödinger's Cat by Adam Hart-Davis. It goes through different eras of scientific thought, listing out important scientific discoveries of each time period. I finished reading the very fast chapter, focusing on the ancient thinkers (before the Enlightenment, that is) yesterday, and I found one of the sections to be especially intriguing.

This section talked about Theodoric of Freiberg, a Middle Ages German clergyman turned scientist who attempted to explain why the rainbow was colored the way it was. His explanation was original and verified by experiment. The one big thing is that it was entirely wrong.

Theodoric believed the rainbow was not made of a continuous spectrum (red, orange, yellow, green, blue, indigo, purple). Rather, he believed there were four dominant colors: red, yellow, green, and blue. Red and yellow were "clear" or translucent colors; blue and green were "obscure" or opaque. 

He performed several experiments to verify his thoughts, such as passing sunlight through a glass prism and looking at the sun through a flask full of water so as to model a raindrop.

Somehow, Theodoric's conclusions turned out to be correct though his explanations had been all wrong. Still, he can be commended for using the scientific theory - proposing a hypothesis and then testing it.

Nematodes! (Part I)

So I am finally done with my internship and free to write! And since I spent a whole month at Caltech studying nematodes, I thought I'd give you guys a little introduction into what they are and what I did there.

Here we go: a nematode is a roundworm. Some are free-living (usually in soil) while others are parasitic. The species of nematode that is studied most often is C. elegans (Caenorhabditis elegans), which is also considered a model organism, meaning that it is easy to maintain and easy to work with. It is a free-living variety and has essentially been domesticated for the lab.

I, too, worked with C. elegans for the majority of my lab work. My project involved the ecology of C. elegans, particularly what food it prefers. In the wild, C. elegans dines on soil bacteria. In the lab, it usually eats a strain of E. coli called op50. The point of the project I worked on was to determine which bacteria the worms preferred, other than op50.

To be continued in Part II...

Getting Back Into Things

So I know I've been gone for a while, but it's almost the end of school (just two more days!) and I hope I'll be able to get back into things. I really want to start posting more often over the summer, though it may be a little difficult with my internship and whatnot. Anyway, I'm so glad to be back and I'm looking forward to lots of new posts!

Happy Holidays!

Happy Holidays! And Merry (Late) Christmas!

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