How close is the nearest black hole to Earth?

Until recently it was impossible to give an exact answer on bow close is the nearest black hole to Earth but an international team of astronomers has for the first time accurately measured the distance from Earth to a black hole, and this distance is 7800 light years, which is much closer that many scientists assumed it is.

How did they measure this distance? The breakthrough discovery was in this case the result of measuring the radio emissions from the black hole and its associated dying star. An exact distance from black hole is important from two different reasons. First of all astronomers can now gain a better picture of how black holes evolve, and what is even more important an exact distance is important for measurements of the black hole´s spin.

This nearest black hole was the result of supernova explosion, and it moves through space at a rate of about 40 km per second.

Scientists hope that with the help of this new measuring method they'll be able "to answer the question as to whether there is a difference between black holes that evolve directly from the collapse of a star without a supernova and black holes that evolve via a supernova and a temporary intermediate star, a proto-neutron star. We expect that the black holes in the last group can get a kick. Black holes formed in this way could then move through space faster", as Peter Jonker from SRON Netherlands Institute for Space Research said in his interview.

Energy drinks - Good or bad for you?

Energy drinks are becoming more and more popular worldwide, for instance 1.5 billion cans of Red Bull were sold in the United States in 2004. This is because many young people, especially students consume these energy drinks in order to increase their concentration during long study through the night. But are these popular energy drinks good or bad for you?

These energy drinks are made up of caffeine and sugar, and according to scientists they have negative impact on human body because they don't hydrate the body efficiently simply because they have too much sugar in it. And caffeine on the other hand doesn't always improve physical performance, especially in large quantities when it can even significantly increase the risks of fatigue and dehydration.

Consumption of Vodka Red Bull could lead to all sorts of trouble since it gives you the feeling you're not drunk though you very much are drunk.

And not only these as several different studies showed how strong doses of caffeine can increase hypertension, cause heart palpitations, provoke irritability and anxiety as well as cause headaches and insomnia. So it is definitely not wise to consume more than two cans a day.

However many young people consume lot more than two cans a day, and what is even worse almost 50 % of young people in US between 18-24 have admitted that they consume these energy drinks mixed with alcohol, and especially popular are Vodkas Red Bull. Consumption of Vodkas Red Bull is dangerous because it cancels the warning signs that the person is actually drunk. In many cases when someone consumes too much alcohol, their head spins and they feel tired but energy drinks cancel this effect so person thinks it is sober but in fact it is very much drunk. This can of course lead to all sorts of troubles.

Earth's outer core consists of which materials?

Despite an impressive technological advances scientists still know very little about Earth's interior. It is a bit odd that we seem to be gathering knowledge about distant planet and far galaxies while at the same time we know so little about our own planet.

Scientists at the University of Calgary hope to put more light on the interior of our planet, specifically the outer core, and their latest findings have been published in the May edition of the journal Physics of the Earth and Planetary Interiors.

They have gathered valuable data by observing distant earthquakes, and according to them these earthquakes can provide valuable clues about Earth's outer core. One of the lead scientists, professor Dave Eaton, said that Earth's outer core is composed of molten iron, nickel and other as-yet unknown lighter elements such as silicon, sulfur, carbon or oxygen.

Earth'c core is located almost 3,000 km below the surface (2,891 km), and in order to determine of which materials does the earth's core consists scientists measured the seismic wave speed (speed of sound) at the top of Earth's core.

This method isn't exactly novelty but scientists from the University of Calgary used brand new digital processing approach, which helped them analyze faint signals, produced by 44 earthquakes, and with it they were able to measure the sound speed at the top of Earth's core with unprecedented accuracy.

The results of this study should be of great help to research efforts at laboratories where core composition is studied by simulating extreme pressure and temperature conditions that exist in the Earth's core.