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IGLESIA CATOLICA: THE TALLEST CHURCH IN THE WORLD ULM GERMANY EINSTEIN BORN DANUBE DAN BROWN
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Reply  Message 1 of 12 on the subject 
From: BARILOCHENSE6999  (Original message) Sent: 02/11/2024 04:53

The tallest Church in the world – Ulm

Ulm Cathedral (Ulmer Münster) is the Gothic church with the tallest tower in the world (before the completion of the Sagrada Familia in Barcelona​​Spain) and the fourth tallest structure built before the 20th century, with a tower height of 161.5 meters.

 

The main tower of the church has 768 steps, they reach up to 143 m high, from where you can see the panorama of the city. On clear days, the panorama of the Swiss and Bavarian Alps can be seen from the church tower.

The interior of the cathedral can be visited without charging a fee, and to climb the tower you have to pay €3/person.

YouTube player

Ulm is located on the left bank of the Danube, in the state of Baden Württemberg. The city initially developed as a medieval fair due to its location on the Danube. Today, the fact that the old town is so close to the river adds to the charm of the place. You can take a ferry ride on the Danube from where you can admire the tourist sights closer to the shore.

If you don’t come by car, you don’t have to worry about spending money on public transport, because the city center is small enough to be covered on foot.

Besides the fact that the city houses the church with the highest tower, Ulm is also known because the great physicist Albert Einstein was born here.

Einstein‘s home was destroyed in an Allied raid and never rebuilt. The Einstein Denkmal (Einstein Monument), built in 1979, marks its place opposite the central station.

Another lens reminiscent of the famous Albert Einstein is the Einstein Brunnen (Einstein Fountain) created in 1984 by the sculptor Jürgen Goertz. The bronze sculpture consists of three elements: the missile bar – represents technology, the conquest of the universe and the nuclear threat; a large snail shell representing nature, wisdom and skepticism towards the mastery of human technology, and from this shell emerges the head of the scientist Albert Einstein.

The central square (Marktplatz) is lined with medieval houses with stepped gables.

From the central square you can easily reach the Fishermen’s Quarter (Fischerviertel) on the Blau river – an affluent of the Danube where you can walk along the narrow cobbled alleys and admire the small houses specific to Germany, some of which have been transformed into restaurants, souvenir shops or hotels.

In the Fisherman‘s Quarter is also the Schiefes Haus Ulm – a house leaning over the river supported by its old beams, built in the 14th century and used today as a hotel.

To the south of the Cathedral is the beautiful Town Hall (Rathaus) built in the Gothic style, with frescoes dating back to 1540. Visitors are often surprised to learn that the intricate designs and decorations were largely restored after the devastation of World War II Worldwide.

Originally built in the mid-14th century, it first served as a store before being transformed into an administrative institution. Other attractions of the building include a replica of the 16th-century astronomical clock and the beautiful fountain called Fischkasten (Fish Tank) built in 1482.

Most of the Ulm‘s 15th-century city walls have been well preserved and today provide an excellent means of exploring the old city. Built in 1482 along the banks of the Danube, the walls – originally designed as a deterrent against invaders – today surround the city and offer tourists a way to admire the view and sights that the city of Ulm has to offer. Along the way, you can find numerous cafes and restaurants, as well as peaceful riverside scenery, ideal for picnics.

Another tourist attraction is the German Bread Museum (Deutsches Brotmuseum), which offers a fascinating insight into the history of bread and its baking, from ancient times to modern times. Exhibits cover the entire process, from growing grains and harvesting crops to the social implications of bread (or lack thereof) on the population. The museum also houses an impressive art collection based on these themes, including paintings by well-known artists such as RembrandtDalí or Picasso.

Tourists who have more time to visit the city can choose the UlmCard which includes free transport on any public transport, free entrance to museums or free guided tours. The 24-hour card costs €12/person and the 48-hour card costs €18/person. You can find more details by clicking here.

If you liked our article about Ulm, read our one on Mannheim as well.

https://www.passports.top/en/ulm/


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Reply  Message 2 of 12 on the subject 
From: BARILOCHENSE6999 Sent: 02/11/2024 04:54
Exploring Ulm: Birthplace of Albert Einstein and the World's Tallest Church"  - YouTube

Reply  Message 3 of 12 on the subject 
From: BARILOCHENSE6999 Sent: 02/11/2024 05:04

Einstein Fountain

Albert Einstein's head sticks out of a snail shell stacked on a rocket in this truly bizarre monument to the scientist. 

75
169

ULMGERMANY, IS PEPPERED WITH monuments to its most famous son, Albert Einstein, who was born in the city in 1879. But none are as bizarre as this unusual fountain. A rocket shoots water from its bottom, forming the base of the fountain. It’s crowned by a large snail shell covered in what looks like a cosmic and terrestrial map. Einstein’s head pokes out of the shell, wide-eyed and sticking its tongue out.

The odd stack of items is more than a silly mishmash of random objects. It’s meant to be a bit of satire, a small piece of social commentary on humanity’s quest to manipulate and control the natural world. The rocket represents technology, particularly the scientist’s legacies involving spacetime and atomic theory. The snail shell symbolizes nature and wisdom. Einstein’s silly expression and weirdly life-like brown eyes show a side of the famous scientist all people, young and old, can relate to.

Artist Jürgen Goertz erected the fountain in 1984. Perhaps what’s most strange about his memorial to the pacifist Einstein is that it’s located next to the old arsenal.

https://www.atlasobscura.com/places/einstein-fountain

Reply  Message 4 of 12 on the subject 
From: BARILOCHENSE6999 Sent: 02/11/2024 05:12
PIN, Ulm Minster, tallest church in the world by Two Small Potatoes travel

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From: BARILOCHENSE6999 Sent: 06/11/2024 05:29
The Great Pyramid and Jesus - Adept Initiates

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From: BARILOCHENSE6999 Sent: 13/11/2024 03:32
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Reply  Message 7 of 12 on the subject 
From: BARILOCHENSE6999 Sent: 16/11/2024 17:12
Einstein's Legacy: Studying Gravity in War and Peace

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From: BARILOCHENSE6999 Sent: 25/11/2024 19:36
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Reply  Message 9 of 12 on the subject 
From: BARILOCHENSE6999 Sent: 30/11/2024 03:53

Utah Elevated: Cathedral of the Madeleine in SLC - YouTube

Jordan River (Utah)

 
 
From Wikipedia, the free encyclopedia
 
Jordan River
Proveau's Fork, West Jordan River
Jordan River Dam, 1908-01-28.jpg
Dam at Jordan River Narrows in 1901
Jordan River Utah with locator map.png
Map of the Jordan Subbasin and the location of Salt Lake County in Utah (inset)
Etymology Named after the Jordan River
Location
Country United States
State Utah
Counties UtahSalt Lake
Physical characteristics
Source Utah Lake
 • location Utah CountyUtah
 • coordinates 40°21′34″N 111°53′40″W[1]
 • elevation 4,489 ft (1,368 m)(compromise level)[2]
Mouth Great Salt Lake
 • location Davis CountyUtah
 • coordinates 40°53′52″N 111°58′25″W[1]
 • elevation 4,200 ft (1,300 m)(historical average)[3]
Length 51.4 mi (82.7 km)[4]
Basin size 791 sq mi (2,050 km2)[5]
Discharge  
 • location mouth
 • average 524 cu ft/s (14.8 m3/s)

The Jordan River, in the state of Utah, United States, is a river about 51 miles (82 km) long. Regulated by pumps at its headwaters at Utah Lake, it flows northward through the Salt Lake Valley and empties into the Great Salt Lake. Four of Utah's six largest cities border the river: Salt Lake CityWest Valley CityWest Jordan, and Sandy. More than a million people live in the Jordan Subbasin, part of the Jordan River watershed that lies within Salt Lake and Utah counties. During the Pleistocene, the area was part of Lake Bonneville.

Members of the Desert Archaic Culture were the earliest known inhabitants of the region; an archaeological site found along the river dates back 3,000 years. Mormon pioneers led by Brigham Young were the first European American settlers, arriving in July 1847 and establishing farms and settlements along the river and its tributaries. The growing population, needing water for drinking, irrigation, and industrial use in an arid climate, dug ditches and canals, built dams, and installed pumps to create a highly regulated river.

Although the Jordan was originally a cold-water fishery with 13 native species, including Bonneville cutthroat trout, it has become a warm-water fishery where the common carp is most abundant. It was heavily polluted for many years by raw sewage, agricultural runoff, and mining wastes. In the 1960s, sewage treatment removed many pollutants. In the 21st century, pollution is further limited by the Clean Water Act, and, in some cases, the Superfund program. Once the home of bighorn sheep and beaver, the contemporary river is frequented by raccoonsred foxes, and domestic pets. It is an important avian resource, as are the Great Salt Lake and Utah Lake, visited by more than 200 bird species.

Big CottonwoodLittle CottonwoodRed Butte, Mill, Parley's, and City creeks, as well as smaller streams like Willow Creek at Draper, Utah, flow through the sub-basin. The Jordan River Parkway along the river includes natural areas, botanical gardens, golf courses, and a 40-mile (64 km) bicycle and pedestrian trail, completed in 2017.[6]

Course[edit]

The Jordan River is Utah Lake's only outflow. It originates at the northern end of the lake between the cities of Lehi and Saratoga Springs. It then meanders north through the north end of Utah Valley for approximately 8 miles (13 km) until it passes through a gorge in the Traverse Mountains, known as the Jordan Narrows. The Utah National Guard base at Camp Williams lies on the western side of the river through much of the Jordan Narrows.[7][8] The Turner Dam, located 41.8 miles (67.3 km) from the river's mouth (or at river mile 41.8) and within the boundaries of the Jordan Narrows, is the first of two dams of the Jordan River. Turner Dam diverts the water to the right or easterly into the East Jordan Canal and to the left or westerly toward the Utah and Salt Lake Canal. Two pumping stations situated next to Turner Dam divert water to the west into the Provo Reservoir CanalUtah Lake Distribution Canal, and Jacob-Welby Canal. The Provo Reservoir Canal runs north through Salt Lake County, Jacob-Welby runs south through Utah County. The Utah Lake Distribution Canal runs both north and south, eventually leading back into Utah Lake.[9] Outside the narrows, the river reaches the second dam, known as Joint Dam, which is 39.9 miles (64.2 km) from the river's mouth. Joint Dam diverts water to the east for the Jordan and Salt Lake City Canal and to the west for the South Jordan Canal.[10][11][12]

A map showing the Salt Lake Valley. It shows the locations of the cities inside the valley with mountain ranges on either side of the valley.
Map of the Salt Lake Valley

The river then flows through the middle of the Salt Lake Valley, initially moving through the city of Bluffdale and then forming the border between the cities of Riverton and Draper.[7] The river then enters the city of South Jordan where it merges with Midas Creek from the west. Upon leaving South Jordan, the river forms the border between the cities of West Jordan on the west and Sandy and Midvale on the east. From the west, Bingham Creek enters West Jordan. Dry Creek, an eastern tributary, combines with the main river in Sandy. The river then forms the border between the cities of Taylorsville and West Valley City on the west and Murray and South Salt Lake on the east. The river flows underneath Interstate 215 in Murray. Little and Big Cottonwood Creeks enter from the east in Murray, 21.7 miles (34.9 km) and 20.6 miles (33.2 km) from the mouth respectively. Mill Creek enters on the east in South Salt Lake, 17.3 miles (27.8 km) from the mouth. The river runs through the middle of Salt Lake City, where the river travels underneath Interstate 80 a mile west of downtown Salt Lake City and again underneath Interstate 215 in the northern portion of Salt Lake City. Interstate 15 parallels the river's eastern flank throughout Salt Lake County. At 16 miles (26 km) from the mouth, the river enters the Surplus Canal channel. The Jordan River physically diverts from the Surplus Canal through four gates and heads north with the Surplus Canal heading northwest. Parley's, Emigration, and Red Butte Creeks converge from the east through an underground pipe, 14.2 miles (22.9 km) from the mouth.[7] City Creek also enters via an underground pipe, 11.5 miles (18.5 km) from the river's mouth. The length of the river and the elevation of its mouth varies year to year depending on the fluctuations of the Great Salt Lake caused by weather conditions. The lake has an average elevation of 4,200 feet (1,300 m) which can deviate by 10 feet (3.0 m).[3] The Jordan River then continues for 9 to 12 miles (14 to 19 km) with Salt Lake County on the west and North Salt Lake and Davis County on the east until it empties into the Great Salt Lake.[7][8][11]

Discharge[edit]

The United States Geological Survey maintains a stream gauge in Salt Lake City that shows annual runoff from the period 1980–2003 is just over 150,000 acre-feet (190,000,000 m3) per year or 100 percent of the total 800,000 acre-feet (990,000,000 m3) of water entering the Jordan River from all sources. The Surplus Canal carries almost 60 percent of the water into the Great Salt Lake, with various irrigation canals responsible for the rest. The amount of water entering the Jordan River from Utah Lake is just over 400,000 acre-feet (490,000,000 m3) per year. Inflow from the 11 largest streams feeding the Jordan River, sewage treatment plants, and groundwater each account for approximately 15 percent of water entering the river.[13]

Watershed[edit]

The Jordan River Basin is in northern Utah.
Map of the entire Jordan River Basin

 

Jordan River
Proveau's Fork, West Jordan River
Jordan River Dam, 1908-01-28.jpg
Dam at Jordan River Narrows in 1901
Jordan River Utah with locator map.png
Map of the Jordan Subbasin and the location of Salt Lake County in Utah (inset)
Etymology Named after the Jordan River
Location
Country United States
State Utah
Counties UtahSalt Lake
Physical characteristics
Source Utah Lake
 • location Utah CountyUtah
 • coordinates 40°21′34″N 111°53′40″W[1]
 • elevation 4,489 ft (1,368 m)(compromise level)[2]
Mouth Great Salt Lake
 • location Davis CountyUtah
 • coordinates 40°53′52″N 111°58′25″W[1]
 • elevation 4,200 ft (1,300 m)(historical average)[3]
Length 51.4 mi (82.7 km)[4]
Basin size 791 sq mi (2,050 km2)[5]
Discharge  
 • location mouth
 • average 524 cu ft/s (14.8 m3/s)
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Reply  Message 10 of 12 on the subject 
From: BARILOCHENSE6999 Sent: 01/12/2024 16:54
Budismo y física (II) | Centro Budista de Valencia

Reply  Message 11 of 12 on the subject 
From: BARILOCHENSE6999 Sent: 02/12/2024 13:54
 

The realm of relativistic hydrodynamics

Modeling relativistic fluids and the phenomena associated with them – from supernovae and jets to merging neutron stars

AN ARTICLE BY JOSÉ ANTONIO FONT RODA

Hydrodynamics or fluid dynamics is the study of the behaviour of fluids such as water and air – water flowing down a canal, but also, for instance, air flowing around an airplane fuselage. The term relativistic hydrodynamics (or relativistic fluid dynamics) refers to the study of flows in the arena of special or of general relativity. Special relativity will come into play when the velocities attained by certain portions of the fluid or by the fluid as a whole approach the speed of light. General relativity comes into play when there are sufficiently strong gravitational fields – either because the fluid’s environment features such fields, or because the mass and energy of the fluid are sufficient to generate their own strong gravity.

The flows we are accustomed to in daily life are a far cry from meeting either of the two conditions – even the flows encountered by a supersonic aircraft amount to no more than a fraction of a percent of the speed of light, and within the whole solar system, there are no really strong sources of gravity altogether. However, such extreme conditions, where hydrodynamics becomes relativistic, are routinely encountered by astronomers observing some of the most violent events in the cosmos.

In fact, almost any phenomenon astronomers observe in the context of what is suitably called high-energy astrophysics requires a relativistic description. In order to understand the dynamics and evolution of such phenomena (we’ll get around to some impressive examples, below), astrophysicists usually resort to mathematical models which incorporate relativistic hydrodynamics as a key building block.

The challenge of relativistic hydrodynamics

The equations describing relativistic hydrodynamics are remarkably complex. In addition to Einstein’s description of gravity, space and time – which entails equations that are already quite complex all by themselves – they must also incorporate proper models for the properties and behaviour of matter, for instance how it flows or reacts to external pressure. For very idealised situations it might be possible to do the calculations by hand, writing down explicit formulae describing the dynamics. An example would be the collapse of a shell that is perfectly spherical (and thus perfectly symmetrical) and made of matter which has very simple properties, dust, for instance, which has no internal pressure to resist gravity, and which thus collapses readily to form a black hole. But for more realistic matter models, which are necessarily more complicated and without any assumption of symmetry, the only option left is to perform computer simulations, in other words: to use the techniques of numerical relativity.

Such simulations have become a powerful way to improve our understanding of the dynamics and evolution of the different kinds of relativistic flows encountered in physics. In particular, this is true for astrophysical systems which, given their size and mass, do not lend themselves to laboratory experimentation. Even so, in order to produce realistic simulations, it is necessary to push current computer technology and programming to their very limits. Indeed, progress in the field is closely tied to advances in the capabilites (such as speed and memory) of (super-)computers on the one hand, and to improvements in the design of ever more efficient and accurate simulation algorithms on the other.

Let us now take a quick tour of the astrophysical realm of relativistic hydrodynamics.

Collapse

We start with a paradigmatic example for the necessity of relativistic hydrodynamics: the collapse of the core of a massive star in the course of a supernova explosion, leading to the formation of extremely compact objects – neutron stars or possibly even black holes.

As the core of the star collapses, it reaches enormous densities – at peak values, matter is so compressed that a tablespoon full would have a mass of more than a hundred million tons – and the dynamic evolution is highly interesting, from the core literally bouncing back as the properties of matter change to the formation of travelling disturbances (shocks). During its fall, the matter can reach velocities up to 40 percent of the speed of light. For the collapse itself, Newtonian gravity and Einstein’s general relativity give markedly different predictions – in Einstein’s theory, gravity in the central regions is up to 30 percent stronger. This makes a relativistic description of hydrodynamics and gravity absolutely essential, especially in the case of a rotating inner core, where there is a delicate balance between the centrifugal forces associated with rotation and gravity’s inward pull. The following animation is based on a relativistic simulation of a collapsing stellar core:

star_collapse

[Image: AEI/ZIB/LSU. Animation size 942kB; please allow time for loading.]

Download movie version (mpeg, 19MB) here

The colors encode the different densities; during the animation, you can see the formation of a red-orange region that is the neutron star. The red and green patterns projected onto an imaginary plane beneath the newly formed star towards the end of the animation represent the gravitational waves produced during the collapse.

As a result of the core bouncing back, the outer layers of the star are ejected. This starts off the supernova explosion with its massive increase in brightness that allows astronomers here on earth to observe these phenomena even when they happen in other galaxies! The debris of the explosion makes for beautiful astronomical objects such as the supernova remnant N63a in one of our neighbouring galaxies, the Large Magellanic Cloud:

 

Supernova remnant N63a

[Image: NASA/ESA/HEIC/Hubble Heritage Team (STScI/AURA)]

Core collapse is not the only way to make a supernova. Alternatively, we might be dealing with a White dwarf star – the remnant of a low-mass star like our Sun – capturing matter from an orbiting companion. Once a critical mass is reached, the White Dwarf will disintegrate in a thermonuclear explosion, leading to what astronomers call a supernova of type Ia.

 

Relativistic jets

Another very common phenomenon where relativistic hydrodynamics comes into play is the formation of so-called jets – situations in which matter flows onto a compact body, and some of the matter being flung away in a pair of tightly focussed beams! If this happens around a compact object of a few or a few dozen solar masses, we have what is called a microquasar; if the central object is much more massive, with a couple of millions or even billions of solar masses, we are dealing with an active galactic nucleus. The following image shows an example, the radio galaxy 3C272.1. In the close-up, one can clearly see the two tight beams emitted in opposite directions from the central core:

 

nrao_ngc4374

[Image: NRAO/AUI/NSF]

In fact, in the jets of many extra-galactic radio sources associated with active galactic nuclei, it seems as if matter were propagating faster than the speed of light! While this is just an optical illusion caused by matter moving near the speed of light, and almost directly towards or directly away from the observer, for this optical effect to occur, the jets’ flow velocities must be at least as large as 99% of the speed of light . One example, a blob of plasma (left) moving away from the core of an object called a blazar (an active galactic nucleus whose approaching jet is seen almost exactly head-on), is shown in the sequence below:

 

 

nrao_0827_243

[Image: Piner et al., NRAO/AUI/NSF]

The object is the blazar 0826+243, and the plasma blob appears to move at 25 times the speed of light – while, in reality, it “only” moves at more than 99.9% of lightspeed.

 

Astronomers have made many high-resolution radio observations of jets, revealing a wealth of form and structure. Using the equations of relativistic hydrodynamics, together with the equations governing the dynamics of magnetic fields and the interactions of such fields with matter (“relativistic magneto-hydrodynamics”), it is possible to explain how these structures come about. In recent years, researchers have managed to perform quite detailed simulations of relativistic jets. An example can be seen in the animation below, which shows the evolution of a powerful jet as it propagates through the intergalactic medium:

 

jetsim

[Image: Max Planck Institute for Astrophysics/L. Scheck et al. in Mon. Not. R. Astron. Soc., 331, 615-634, (2002).]

For the main structures observed in the simulations – for instance propagating discontinuities in the beam, and a hot spot at the head of the jet – astronomers can find counterparts as they observe extragalactic radio sources.

 

Gamma ray bursts

A relativistic description of gravity and of the dynamics of matter is also necessary in scenarios involving the gravitational collapse of massive stars (with masses of about 30 solar masses and higher) to form black holes, or during the last phases of the coalescence of two neutron stars which orbit each other. These two explosive events are believed to be the mechanisms responsible for the so-called gamma-ray bursts, the most luminous events in the universe short of the big bang itself. In particular, stellar collapse is considered the mechanism behind what are called “long” gamma-ray bursts, the bursts lasting for about 20 seconds, while neutron star mergers are regarded as responsible for “short” gamma-ray bursts, with a duration of only about 0.2 seconds. The following animation shows on the left a false colour image of the gamma rays received from the different regions of the whole sky, using data collected with NASA’s Compton Gamma Ray Observatory. As you can see, there is a bright flash in the top half which, at one time, is so bright that it dominates the whole of the image. This is one particular gamma ray burst; the curve on the right traces how the burst’s brightness changes over time:

 

grb_animation

[Image: NASA’s “Imagine the Universe!” website]

Since the gamma-ray bursts take place at a distance of billions of light years from Earth, the fact that, even at that distance, they are visible as extremely bright phenomena implies that huge amounts of energy must be released – comparable to converting the mass of our sun completely into gamma-rays over the course of a few seconds within a region of space no more than a couple of thousand kilometres across. There is general agreement, supported by observational evidence, that the gamma rays are not emitted in all directions (such as the emissions of a light bulb), but that they are focussed (such as the light from the beam of a lighthouse, which you only see if it is pointed directly at you). The focussing accounts for some part of their perceived brightness, and it would mean we observe only those gamma ray bursts whose light happens to be emitted exactly in the direction of the Earth. The mechanism for this focussing would be, once more, matter moving at relativistic speeds to form some kind of jet. Theoretical models estimate that the matter responsible for the gamma-ray burst emission must be travelling at more than 99.99% of the speed of light.

 

Simulations of how this movement comes about and causes an event as spectacular as a gamma ray burst are, once more, the province of relativistic hydrodynamics. For short gamma ray bursts, these simulations need to track the merger of two orbiting neutron stars. The following animation illustrates one such simulation, where each of the two neutron stars has 1.4 times as much mass as our sun:

 

ns_merger

[Image: M. Shibata, Tokyo University. Animation size 651kB; please allow time for loading.]

Download movie version (mpeg, 6.6MB) here.

 

The final stage of the merger which is shown here would take about 3 thousandth of a second from start to finish. In the animation, the colors encode different densities, while the velocity of matter in different regions is represented by little arrows.

There is an additional aspect to all these astrophysical scenarios: The presence of both relativistic flows and massive yet compact objects turns them into prime candidates for the production of gravitational waves! The possibility of directly detecting these elusive ripples in the curvature of spacetime, and of extracting a wealth of new information from the data, is one of the driving motivations of present-day research in relativistic astrophysics – and faithful modelling of these situations using relativistic hydrodynamics is a key ingredient of successful gravitational wave astronomy!

Man-made relativistic flows

While natural flow processes here on Earth are a far cry from reaching relativistic speeds, there are indeed artificial – man-made – relativistic flows, namely in particle accelerators. One example is the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory in New York, which began operation in 2000, another the Large Hadron Collider (LHC) at CERN near Geneva, which is currently under construction.

In these facilities heavy ions – heavy atomic nuclei, for instance those of gold or lead, stripped of their electrons – are accelerated to ultra-relativistic velocities and made to collide with one another. At RHIC, the projectiles travel at typical speeds of 99.995% the speed of light – at such speed, the relativistic mass of a moving object is more than a hundred times larger than its mass at rest! After the LHC has started its operations in late 2007, there will be the possibility for experiments in which the mass – and energy – will be increased by almost a factor of one hundred.

Heavy-ion collision experiments provide a unique way to compress and heat up nuclear matter, and to prove the existence of an exotic state of ultra-compressed nuclear matter, called a quark-gluon-plasma, which is predicted by the theory of strong nuclear interactions (quantum chromodynamics). They recreate, within a tiny region of space, conditions similar to those under which matter existed in the early universe, fractions of a second after the big bang.

Physicists use several techniques do describe what happens in these collisions. A number of results can be obtained by treating all the particles involved as separate objects. But for other calculations, it is much more useful to treat the dense, strongly interacting matter formed in the collision as a continuous fluid. Of course, given the energies involved, we need to take into account the effects of special relativity. As an example, the following animation shows results of a simulation of a jet – a particle stream produced in such collisions – propagating through a simplified version of such a fluid, producing a Mach cone similar to the sonic boom of a supersonic aircraft:

 

mach_cone

[Animation B. Betz, Goethe-Universität Frankfurt.]

Numerical simulations with relativistic fluid models have proved to be of great help in understanding certain aspects of these highly energetic heavy-ion collisions.

 

Further Information

Relativistic background information for this Spotlight topic can be found in Elementary Einstein, in particular in the chapter Black Holes & Co..

Further related Spotlights on relativity can be found in the category Black Holes & Co..

Further information about some of the animations displayed in this text:

Further simulations from Albert Einstein Institute’s numerical relativity group can be found on the numrel@aei homepage.

A variety of other simulations of merging neutron stars are accessible on Masaru Shibata’s Homepage.

NASA’s Imagine the universe! website has a wealth of accessible material about all areas of astrophysics.

Presentations by Barbara Betz containing further simulations can be downloaded from the Helmholtz Research School Presentation page.

https://www.einstein-online.info/en/spotlight/hydrodynamics_realm/

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Does space "flow" like a river? There's an analogy in General Relativity ... Why The Theory of Relativity Doesn't Add Up (In Einstein's Own Words).


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