4

Mostly Mute Monday: A GLIMPSE of the galaxy

"This data will enable scientists to build the most accurate model ever of star-formation, history and evolution within our galaxy, and understand the mechanism behind the origin of practically all the light in our Universe."

There’s nothing quite like the plane of our Milky Way galaxy. Some 200-400 billion stars are located there, including our own Sun. From our vantage point within it, most of these are obscured by the dust lanes present within. But thanks to its views in infrared light, the Spitzer Space Telescope can glimpse not only all of the stars and the dust simultaneously, it can do it at an alarming resolution. Recently, NASA has put together a 360° panorama of more than 2,000,000 Spitzer images taken from 2003-2014, and I’ve gone and stitched them together into a single, 180,000-pixel-long viewable experience that shows less than 3% of the sky, but nearly 50% of its stars.

youtube

Could the Milky Way Become a Quasar?

There’s a supermassive black hole in the center of our Milky Way galaxy. Could this black hole become a Quasar?

By: Fraser Cain.
Support on Patreon: http://www.patreon.com/universetoday

Κωνικά, i.e. the ugly shadow of algebraic geometry

When one imagines the paths along which various space objects travel what ordinarily comes into mind are circles - all the popular pictures of our solar system picture planets (the fact that Pluto has been reclassified strengthens my point because it was the only object (except for a random comet which an artist threw in) which was difficult) as encircling our sun for example. It’s less circles and more of stuff like this

and this

Indeed, the solutions to Newton’s equations of motion for one gravitating body are much richer than ordinary, boring circles. Circular orbits are but a special case of shapes that encompass ellipses, hyperbolas, parabolas etc. 

To learn about those, lets go back to the Hellenistic world, the time when Ptolemaic Aegypt and Kingdom of Pergamon were the most important scientific centres of the world. One can remember both of those for impressive libraries, but they were housing also various different institutions of higher learning like Musaeum and University of Alexandria. In similar way as today mathematicians, scientists and philosophers were working and doing research there, using the financing provided by the governments of Hellenistic countries (not only that, but they also often moved between those centres, as scientists of today who are always trying to find a place where they can be paid a living wage in the sad reality of under-financed science).

Apollonius of Perga was one of those mathematicians. We know him from his multiple tomes treatise Κωνικά (gr. Conics), which topic is all about ellipses, parabolas and hyperbolas. Essentially, those are curves that one can obtain by intersecting a cone and a plane (hence the name “conics”). In modern parlance, if you are algebraic geometrically inclined (and if you are indeed, I’ll be judging you), those are examples of algebraic curves, which are described by polynomial equations.

However, Apollonius was not only interested in pure mathematics - among his interests was also astronomy, in particular the movement of the Moon and the theory of epicycles. It is not a stretch to think that the abstract treatment of geometry and the possible applications to astronomy were intertwined, although it is somewhat difficult to tell because much of this knowledge were irreparably lost with the fall of the ancient Greek civilisation. With the hindsight it is easy for us to see that those two things are really closely related - all of us learn in the school about Johannes Kepler (and Isaac Newton) and his three laws of planetary motion, and the first of those is that planets travel along ellipses. So, in order to figure out how planets and satellites and space stuff move it is essential to look into ellipses (the topic of hyperbolas and parabolas we will tackle another time) more in-depth.

As previously in the case of a circle, ellipse is described by the quadratic equation

$$\left( \frac{x}{a} \right)^2 + \left( \frac{y}{b} \right)^2 = 1,$$

where $a$ and $b$ are real numbers which describe the exact shape (how “egg-like” the ellipse is). Obviously, setting $a=b=R$ returns us to the case of a circle, so we see that it is indeed a special case. We can plot it to have something pretty to look at, by e.g. using the following Mathematica code

ellipse = x^2/a^2 + y^2/b^2 == 1;
ContourPlot[(ellipse /. a -> 5 /. b -> 1) // Evaluate, {x, -5,
 5}, {y, -1.5, 1.5}, Axes -> True, AxesStyle -> Black,
Frame -> False]

which gives us the graph like this

This equation is implicit - however, we can parametrise it, using an angle $\omega t$ or time $t$ as

$$ x = a \sin(\omega t + \phi),$$ $$ y = b \cos(\omega t + \phi), $$

where $\phi$ is the angle from which we start, and $\omega$ is angular velocity. Now, to verify that this parametrisation is indeed of a parametrisation of an ellipse, it is sufficient to plug this to the implicit equation and use the the Pythagorean identity

Now, looking back at the “space” pictures, one can notice that the planet is not in the centre of the coordinate system. In fact, it is located in somewhat special point called a focus. But that will be a subject of another post…

NGC 7822

Processing: Francesco Antonucci; Data: WISE IRSA Archive

A young star forming complex in the constellation of Cepheus.

The complex encompasses the emission region designated Sharpless 171, and the young cluster of stars named Berkeley 59.

The complex is believed to be some 800-1000 pc distant, with the younger components aged no more than a few million years.

X-Rays from our Sun

High-energy solar emissions can be seen in blue and green protruding from solar gasses. NASA has been studying these solar X-rays in detail with it’s Nuclear Spectroscopic Telescope Array sense 2012. In this image, NuSTAR data was combined with NASA’s Solar Dynamics Observatory to better understand the structures of solar arches.

Credit: NASA/JPL/NuSTAR

No one knew exactly what a black hole would look like until they actually built one. Light, temporarily trapped around the black hole, produced an unexpectedly complex fingerprint pattern near the black hole’s shadow. And the glowing accretion disk appeared above the black hole, below the black hole, and in front of it. “I never expected that,” Thorne says. “Eugénie just did the simulations and said, ‘Hey, this is what I got.’ It was just amazing.”

In the end, Nolan got elegant images that advance the story. Thorne got a movie that teaches a mass audience some real, accurate science. But he also got something he didn’t expect: a scientific discovery. 

MORE: Wrinkles in Spacetime: The Warped Astrophysics of Interstellar 

Gigantic Ring System Around J1407b Much Larger, Heavier Than Saturn’s

Astronomers at the Leiden Observatory, The Netherlands, and the University of Rochester, USA, have discovered that the ring system that they see eclipse the very young Sun-like star J1407 is of enormous proportions, much larger and heavier than the ring system of Saturn.

The ring system – the first of its kind to be found outside our solar system – was discovered in 2012 by a team led by Rochester’s Eric Mamajek.

A new analysis of the data, led by Leiden’s Matthew Kenworthy, shows that the ring system consists of over 30 rings, each of them tens of millions of kilometers in diameter.

Furthermore, they found gaps in the rings, which indicate that satellites (“exomoons”) may have formed. The result has been accepted for publication in the Astrophysical Journal.

“The details that we see in the light curve are incredible. The eclipse lasted for several weeks, but you see rapid changes on time scales of tens of minutes as a result of fine structures in the rings,” says Kenworthy. “The star is much too far away to observe the rings directly, but we could make a detailed model based on the rapid brightness variations in the star light passing through the ring system. If we could replace Saturn’s rings with the rings around J1407b, they would be easily visible at night and be many times larger than the full moon.”

7

Wonderful. Chromoscope:

Ever wanted X-ray specs or super-human vision? Chromoscope lets you explore our Galaxy (the Milky Way) and the distant Universe in a range of wavelengths from gamma-rays to the longest radio waves.

From top to down:

Quick Tour of Chromoscope

The Fairy of The Eagle Nebula - M16

"The dust sculptures of the Eagle Nebula are evaporating. As powerful starlight whittles away these cool cosmic mountains, the statuesque pillars that remain might be imagined asmythical beasts. Pictured above is one of several striking dust pillars of the Eagle Nebula that might be described as a gigantic alien fairy. This fairy, however, is ten light years tall and spews radiation much hotter than common fire. The greater Eagle Nebula, M16, is actually a giant evaporating shell of gas and dust inside of which is a growing cavity filled with a spectacular stellar nursery currently forming an open cluster of stars. The above image in scientifically re-assigned colors was released in 2005 as part of the fifteenth anniversary celebration of the launch of the Hubble Space Telescope.”

Credit: NASA/Hubble/APOD

2

How a pair of astrophysicists are defying expectations with a science fashion blog

“People are aware that there’s sort of a galaxy theme out there that sometimes are real images and sometimes they’re just artistic renditions, but I don’t think people are aware of the extent of it and how much that expands into all different types of product lines,” Ash told the Daily Dot.

There’s something for everyone on the blog from everyday wear to runway styles, pricy to affordable products, and options for men, women, and children. Looking through all the options is a lot of fun, but you’ll also learn something. As often as possible, they include the name of what you’re seeing displayed on each product such as a galaxy, along with information about it like its age and why scientists are interested in studying it. Dr. Ash said it’s a “come for the fashion, stay for the science” approach.

[Read more]

Spotting black holes is tricky. Because they don’t give off light, astronomers have a difficult time pinpointing their location. But when a black hole gets close enough to an object, like a star, for example, and begins consuming the object’s mass, the matter that pours into its gravitational clutches can get so hot that it glows and releases energy in the form of X-ray light. The most powerful X-rays are emitted from the hottest material swirling just outside the edge of the black hole. By observing this light with space telescopes, scientists can determine where black holes are hiding in the cosmos. Watch the video to see a black hole in action.

Credit: NASA/Swift