This 1946 photograph shows ENIAC (Electronic
Numerical Integrator And Computer), the first general purpose electronic
computer - a 30-ton machine housed at the University of Pennsylvania.
Developed in secret starting in 1943, ENIAC was designed to calculate
artillery firing tables for the United States Army's Ballistic Research
Laboratory. The completed machine was announced to the public on
February 14, 1946. The inventors of ENIAC promoted the spread of the new
technologies through a series of influential lectures on the
construction of electronic digital computers at the University of
Pennsylvania in 1946, known as the Moore School Lectures.#
New
Delhi: The enigmatic universe harbours countless secrets within it,
compelling scientists to put in every effort to delve deeper in order to
extract information about its existence and consequent evolution.
The universe is also home to numerous super-massive black holes,
which emanate incredibly bright and luminous distant points of light
called Quasars.
Using the positioning of these quasars, scientists have now managed
to create the largest, very first map of the large-scale structure of
the universe.
"Because quasars are so
bright, we can see them all the way across the universe," said Ashley
Ross of the Ohio State University in the US.
"That makes them the ideal objects to use to make the biggest map yet," said Ross.
The super-massive back holes are placed right in the centre of the quasars, which give them the brightness.
As matter and energy fall into a quasar's black hole, they heat up to
incredible temperatures and begin to glow. It is this bright glow that
is detected by a dedicated 2.5-metre telescope on Earth.
"These quasars are so far away that their light left them when the
universe was between three and seven billion years old, long before the
Earth even existed," said Gongbo Zhao from the National Astronomical
Observatories of Chinese Academy of Sciences.
In order to make their map, scientists used the Sloan Foundation Telescope to observe an unprecedented number of quasars.
During the first two years of the Sloan Digital Sky Survey's Extended
Baryon Oscillation Spectroscopic Survey (eBOSS), astronomers measured
accurate three-dimensional positions for more than 147,000 quasars.
The telescope's observations gave the team the quasars' distances,
which they used to create a three-dimensional map of where the quasars
are.
However, to use the map to understand the expansion history of the
universe, they had to go a step further, using a clever technique
involving studying "baryon acoustic oscillations" (BAOs).
BAOs are the present-day imprint of sound waves which travelled
through the early universe, when it was much hotter and denser than the
universe we see today.
However, when the universe was 380,000 years old, conditions changed suddenly and the sound waves became "frozen" in place.
These frozen waves are left imprinted in the three- dimensional structure of the universe we see today.
The results of the new study confirm the standard model of cosmology that researchers have built over the last 20 years.
In this standard model, the universe follows the predictions of
Einstein's General Theory of Relativity - but includes components whose
effects we can measure, but whose causes we do not understand. (With PTI inputs)
The European XFEL, the biggest and most powerful X-ray laser in the
world, completed its first lasing. Its key component, the
superconducting linear accelerator developed by DESY, produces electron
streams a billion times brighter than conventional synchrotron X-ray
radiation.
( D. Nölle | DESY )
The European XFEL, the crème de la crème of X-ray radiation lasers currently existent in the world, is up and running and has successfully completed its first lasing.
Scientists at the German research center DESY, in Hamburg, fired the
European XFEL on Thursday, May 4, to witness its first X-ray beam, thus
reaching "the last major milestone" before the facility is officially
opened in September.
"The European XFEL has generated its first X-ray laser light. The
facility, to which many countries around the world contributed know-how
and components, has passed its first big test with flying colors," said Professor Robert Feidenhans'l, European XFEL managing director.
Come autumn, international research teams will be able to harness the
power and accuracy of the X-ray laser for the benefit of scientific
experiments, paving the way for "a new era of research in Europe" and
throughout the world.
By then, DESY and European XFEL representatives estimate two
scientific instruments will be fully operational and ready to welcome
external users. This number will eventually be extended to six.
The Biggest X-Ray Laser In The World
There are only five X-ray lasers worldwide, and the European XFEL is the largest and most powerful laser of them all. The laser is housed in an underground facility that stretches for 3.4 kilometers (or about 2.1 miles).
The European XFEL is an X-ray laser of superlatives. It generates
synchrotron radiation in X-ray range, emitting electrons that are
accelerated to relativistic speed (close to speed of light). Its X-ray
laser is extremely intense and a billion times brighter than conventional synchrotron light sources.
The laser light is produced with what DESY describes as "the most advanced and most powerful linear accelerator in the world."
The first lasing of the European XFEL yielded an X-ray beam of 0.8
nanometers in wavelength, about 500 times shorter than the wavelength of
visible light.
During the test, the X-ray laser recorded a repetition rate of one
pulse per second. Once the European XFE is running at full capacity, the
laser will generate 27,000 pulses per second, each so short and intense
that researchers can make pictures of structures and processes at the
atomic level. By comparison, the previous was of just 120 pulses per
second.
How The European XFEL Works
The laser fires streams of electrons that go through an accelerator
tunnel 2.1 kilometers (or about 1.3 miles) in length. Here, the electron
pulses are accelerated and travel at near-light speed and very high
energies through a photon tunnel.
This tunnel contains a stretch of X-ray generating devices 210 meters
long (or about 689 feet), where a series of more than 17,000 permanent
magnets drive the beams through a lengthy series of mirrored tunnels.
The magnets have alternating poles and are called undulators. They
interact with the electron pulses from above and below, steering the
electrons into a "slalom" course.
At each turn, the beams release extremely short-wavelength X-ray
radiation which magnify over the course of each beam's trip through the
tunnels.
"We can now begin to direct the X-ray flashes with special mirrors
through the last tunnel section into the experiment hall, and then step
by step start the commissioning of the experiment stations," explained
Feidenhans'l.
Cool Scientific Applications For The European XFEL
Once in operation, the key component of the XFEL — the
superconducting linear accelerator — will generate the fastest, most
powerful laser pulses on the planet. The laser facility will also be
extremely versatile, capable of conducting biological, chemical and
physical experiments.
According to a DESY and European XFEL joint news release, the wavelength of
the X-ray laser light corresponds to the size of an atom, which means
that "the X-rays can be used to make pictures and films of the
nanocosmos at atomic resolution."
"The European XFEL will provide us with the most detailed images of
the molecular structure of new materials and drugs and novel live
recordings of biochemical reactions," noted Helmut Dosch, DESY chairman.
In other words, the XFEL will allow scientists to better study
biomolecules, leading to a more complex understanding of how diseases
progress. This will enable researchers to develop novel therapies.
Another scientific application of the European XFEL is a more
comprehensive study of chemical processes and their catalysts, in an
effort to improve their efficiency and make them less harmful to the
environment.
Other areas of interest include materials research and investigating
conditions similar to those found in the interior of planets.
The superconducting linear accelerator was developed by DESY, the
largest shareholder of the European XFEL, and made operational on April
19.
"The European XFEL's particle accelerator is the first
superconducting linear accelerator of this size in the world to go into
operation. With the commissioning of this complex machine, DESY and
European XFEL scientists have placed the crown on their 20-year
engagement in developing and building this large international project.
The first experiments are within reach, and I am quite excited about the
discoveries ahead of us," said Dosch at the time.
