Science: the cosmic web

Cosmic Web, Open Science

***

First of all, astronomers report an observed phenomenon called the cosmic web. The article It's Filamentary says more, including

The distribution of galaxies and matter in the universe is non-random.  Galaxies are organized, even today, in a manner resembling an enormous network – the cosmic web.  This web has dense regions made up of galaxy clusters and groups, sparsely populated regions devoid of galaxies, as well as the filaments that link overdense regions.

“The filaments are like bridges connecting the denser regions in the cosmic web,” [Benham] Darvish explained.  “Imagine threads woven into the web.”

Here's a 3D image of the cosmic web, posted at Dave Reneke's World of Space and Astronomy.

***

The Cosmic Web in 3D, davidreneke

***

Physics Today reported last week that astronomers observe a nascent galaxy stuck to the cosmic web.

***

Nascent galaxy in cosmic web, Physics Today

***

The article mentions a cosmic web imager. To see the lab setup, browse to Caltech's CWI page. Unfortunately, the photos are small. Here's a paper (PDF format) with larger images and some more information: The Keck Cosmic Web Imager.

Spectrography, interchangeable with spectroscopy, is the method used to observe this type of web. According to Wikipedia--

Spectroscopy and spectrography are terms used to refer to the measurement of radiation intensity as a function of wavelength and are often used to describe experimental spectroscopic methods. Spectral measurement devices are referred to as spectrometers, spectrophotometers, spectrographs or spectral analyzers.

For a more granular definition, check out Spectrometer, Spectroscope, and Spectrograph in SPIE's Optipedia. SPIE is an international society advancing an interdisciplinary approach to the science and application of light.

-- Marge

Using science to date an ancient battle

Krishna and Arjun on the chariot, Mahabharata, 18th-19th century, India, Wikipedia

***

Delving into ancient tales for proof of actual events can be tricky to say the least. But the work of Dr. Naraha Achar used such intriguing methods that I must respect in his results. The basis for this post is a video about finding evidence of a sunken city called Dwaraka (Dvārakā) in ancient India. You can find Dr. Achar's research explained from times 14:30 to 19:40 of this long, sometimes rambling video. Approach with caution: there are suggestions of a conspiracy to cover up archaeological findings and intimations of alien technology.

***

***

Dr. Achar's research is based on a long, complex Sanskrit epic of ancient India called the Mahabharata. B. N. Narahari Achar is professor emeritus at the Department of Physics and Materials Science, University of Memphis. There are several opinions on when the Kurukshetra War, the main event described in the Mahabharata, occurred.

Subhash Kak, professor emeritus at the Department of Electrical & Computer Engineering, Louisiana State University, addresses some of these opinions and how complex the Mahabharata is. Check out this paper by him. In his paper he mentions Dr. Acher's research, saying

Recently, the historian of astronomy Narahari Achar has in unpublished work argued for the date of 3067 BC with an error of a few decades. Achar’s work does not depend on the classical siddhantic ideas which increases its persuasiveness. (Note.9)

Author Stephen Knapp also mentions Dr. Achar's work in his Time Line of Lord Krishna article; but I tend to give his writing a wide berth because of this opening line--"As devotees and followers of the Vedic path..."

Some interesting reading can be found under the topic of Archaeoastronomy. To get an idea of how deep and varied human beliefs are, take a look at Wikipedia's Lists of Deities.

I came across this quote from J.R.R. Tolkien the other day:

All that is gold does not glitter,
not all those who wander are lost;
the old that is strong does not wither,
deep roots are not reached by the frost.

-- Marge

Hubble is winking out

NASA/ESA/Hubble Heritage, star-forming region NGC3603, SpaceTelescope

***

Hubble, aka the HST, has given us hundreds, maybe thousands of images of space, like the one above. But it's reaching the end of its lifetime. Scientists say it could  survive through 2020. Many of us watched with great interest as it was being built. A synopsis of Hubble's story is available at the Hubble site. Its optics are amazing. For a detailed description of the telescope's construction, check out Science Clarified's article. Unfortunately, Hubble's mirror in the newly deployed device "was the wrong shape and could not focus properly (Science Clarified)". If you're interested in such here's a link to NASA's Optical Systems Failure Report (a large PDF).

***

Grinding the Hubble mirror, Science Clarified

***

Hot in the news right now is a possible replacement for Hubble, one that doesn't require grinding mirrors or transporting a payload of 24,500 pounds. It's called the Aragoscope, and its technology is revolutionary (when is space technology not?). It's being developed at the University of Colorado-Boulder and scientists there say that it could "provide images up to 1,000 times sharper than the Hubble Space Telescope." This is an illustration of the concept.

***

WebsterCash, Aragoscope illustration, Centauri Dreams

***

The idea originates with Webster Cash and he describes it thus in an article at Centauri Dreams:

Unlike a starshade, the Aragoscope would be circular in shape, an opaque disk whose diffracted light is directed toward a pinhole camera at its center, then to a telescope that provides extremely high resolution views of stellar objects.  

Cash has also developed the starshade concept, but is now calling the Aragoscopy phase 2 of his efforts to develop a new kind of telescope. Paul Gilster at Centauri Dreams comments:

It’s intriguing that the Aragoscope, in some ways, turns Cash’s earlier starshade concepts on their head, aiming for high resolution rather than high contrast. “I spent a lot of time understanding the physics of destroying diffractive waves very efficiently,” he told the magazine. “In the process, it’s not hard to see that you can use those detractive waves to create images.”

Deploying the Aragoscope would be much simpler to launch than the HST, as described by CBS:

The opaque space disk would be made of a strong, dark, plastic-like material (think Hefty bag) that could be launched in a compressed fashion like a parachute, and then unfurled in orbit. The space shield would be tethered to the telescope at distances from tens to hundreds of miles depending on the size of the disk, said Harness [doctoral student Anthony Harness of the Department of Astrophysical and Planetary Sciences].

More information is available at Gizmag and Popular Mechanics.

-- Marge

Science: the black hole conundrum

A high resolution mid-infrared picture taken of the center of our Milky Way galaxy reveals details about dust swirling into the black hole that dominates the region. - Image Credit: Dr. Mark Morris (UCLA) Keck II, Mirlen instrument, keckobservatory.org

***

A number of different astronomers have stated that each galaxy has a supermassive black hole at its center. Or at the least, most galaxies, ours included. How can this be? Modern culture would have us believe black holes suck in all surrounding matter once it crosses the event horizon. A page about black holes at NASA Chats - Ask an expert says:

Black holes are really just the evolutionary end points of massive stars. 

Even more intriguing, but somehow reassuring, too.  The end of life may generate a new beginning. Joseph Conrad's Heart of Darkness keeps coming to mind. An article at Cosmotography--A Singular Place--explores the relationship between a black hole and its surrounding galaxy.

Some interesting work observing the black hole called Sagittarius A*, at the center of our galaxy, the Milky Way, is being done. A relatively new device for observation is NASA's NuSTAR (video posted by Teknociencia).

***

***

Sgr A* is a research topic for astronomer James Lyke at the Keck Observatory in Hawaii. Recently he's captured some good information about the black hole, using several complementary technologies. Note in the video below, posted by the Science Channel, what it takes in terms of manpower and mechanical positioning to capture such information.

***

***

You can track current news about Keck Observatory at this dedicated site.

-- Marge