Since prehistoric times, it is known that on a flat star "carpet" places across holes - areas where the stars or see very little or hardly visible. Particularly well such failures are seen on the background of the milky Way (of course, in those places where the level of illumination of the sky lets you see the milky Way).

Hundreds of years observers believed that the dark failures reflect the actual distribution of the stars, that is, put the sign of equality between "is not visible" and "no". This point of view initially adhered to and Edward Barnard, founder of photographic Atlas of selected areas of the milky Way, published in the beginning of XX century. However, a thorough study of photos convinced him that the nature of dark spots different. They appear where the light of background stars is blocked by clouds absorbing substance. Barnard not only discovered a new type of astronomical objects, but also compiled a list of them - the first catalogue "dark nebulae". Objects from the directory denoted by the letter "B" and number.

In 1947 Bart Side and Edith Reilly noted that among very diverse dark nebulae are allocated separate subspecies: small clouds with a relatively sharp edges and rounded. They offered to call such clouds the globules and suggested that it is in such small dark blobs of stars are born.

Further development of astronomy has shown that this assumption is probably correct. However, since then, has clarified many details. Thanks to the development of radio astronomy was found out, for example, that an absorbing substance - dust - mass accounts for only one percent of the total mass of globules. Basically, they consist of a transparent and thus invisible in optics of natural gas. In addition, in the vast interstellar clouds are also present a tight compact kernel-clots in properties is similar globules, which is, presumably, future stars. Globule just seen more distinctly its relative isolation from the rest of interstellar gas.

Until the beginning of 2000-ies global B68 special attention not attractive, but at the turn of the Millennium things have changed. The turning point in her life was the article Joao Alves, Charles Lada and Elizabeth Lada, published by the journal Nature in the beginning of 2001. The essence of their work was quite simple. Dust in globule, completely closing the background of stars in the visible range, becoming more transparent in the infrared (IR) range. Comparing images B68 at wavelengths from 440 up to 2200 nm nm, Alves with colleagues in force absorption assessed the amount of dust in the directions on 3708 background of stars, of which about a thousand are only visible in the infrared images. The result is a very detailed map of the distribution of dust in globule, however, only two-dimensional, in the projection at the sky.

It turned out that the average azimuth distribution density of dust (and if multiplied by a hundred, and the density of the gas) is very similar to the theoretical distribution of density in a spherical cloud, which is in the state of hydrostatic equilibrium, that is in the cloud, thermal pressure which is exactly balanced by samoogranichitsja and external pressures, the so - called profile of Bonora-Ebert Foundation. Look at this image from the article of Alves and other Such consent theory (line) and observations (red dots) cannot but cause tears of emotion.

Since then, global B68 was not that a benchmark, but a kind of template tsvetanova object. She is close to her about a hundred Persikov. The cross-section in a few minutes of arc allows mapping of globules even on instruments with moderate angular resolution. Therefore, over the past ten years it was observed repeatedly, and in the continuous spectrum, and the lines of molecules.

Excessive attention is not always useful for the reputation. The more data about B68 accumulated, the more questions appear. For example, if global is in equilibrium, as could be seen as its predecessor stars? Balance is the balance to deprive the object prospects. On the stability B68 pointed and chemical analysis. From observations of many globules and nuclei molecular clouds known that the gas in the Central, most dense areas gradually depleted of molecules, because the molecules froze to the dust. In globule B68 this process has gone particularly far reaching even particularly resistant to freezing molecules of nitrogen compounds. This seems to indicate age in millions of years - much more assessments age for other globules and nuclei.

Another strange fact: analysis of Alves with colleagues testified that the balance B68 slightly unstable. That is, any external influence should make globulo to collapsibility. Really for millions of years, it has never experienced such impact? Experienced! In 2003, Charles Lada with colleagues built the map of the movements in globule and Doppler shifts of spectral lines of some molecules found that the material of the cloud is not compressed (as it should be a future star), but rather waves, that is experiencing difficult predelnye ripple, possibly caused by the passage of the shock wave from the supernova. On the one hand, the idea of a supernova logical: it could "blow away" substance molecular clouds, a part of which was once B68, because of what we are now seeing it as an isolated globule. On the other hand, how do we reconcile that with the conclusion on the balance?

In the General complex picture contributed and theorists, published in 2003, an article with the eloquent title "Dynamic kernel in hydrostatic disguise". The theorists life is always easier - they have access to the full range of physical parameters of objects that model. The authors of this article was modeled the formation of nuclei of molecular clouds and was surprised to find that the density profile, very <>is similar to the profile of Bonora-Ebert Foundation, have in their models of the nucleus, which in any case equilibrium are not.

In 2009, Andreas Burkert in collaboration with Alves suggested that all contradictory properties B68 can be explained by the recent collision of this globules with other small kernel that maps looks like a small "tail" in the left bottom part of the globule. And now Marcus Nilbog with co-authors seem to confirm this scenario.

First of all, on maps of the distribution of matter obtained by using "Gershel", clearly highlights global-ullet"hitting below globule- arget". It is seen not as simple process on the main globule, and as a separate object. Highlighted it and kinematic maps: the Doppler shift of spectral lines of carbon monoxide observed in the direction "bullet", says that she is moving relative to "target" at a speed of 1 km/S.

The question is: why is this difference in the rates have not seen before? As I wrote, B68 many times observed in lines. Nilbog with co-authors believe that the authors of previous studies simply not considered such a big difference in speed. Inside these engines the velocity dispersion usually does not exceed several hundred meters per second, so large relative motion could be overlooked. In any case, raising the old observations B68, Nilbog and his colleagues found that a collision could be discovered ten years ago.

Now the fate B68 seems to be finally determined. The collision caused globulo shudder to become unstable - and in some couple of hundred thousand years close to the Sun will light up a new star.