Space mosaic

What is there to see here?

On the radio image you can see a partial image of our sky in the constellation Sagittarius, taken in the direction of the center of our Milky Way. The recorded field is located in the southern sky, which is why it is better observable from the southern hemisphere.

What is the size of the section shown?

The motif shows the sky in a field of about 3×2 degrees. For comparison, the full moon has a diameter of 0.5 degrees. Our solar system is about 8.2 kpc (or 27000 light years) from the center of our galaxy, the Milky Way. From these values we can calculate that the horizontal section of the image has a length of about 430 pc (or 1400 light years).

To explain:

Degree:

In astronomy, the units degrees and arcminutes are often used to measure angles. One degree is divided into 60 minutes of arc.

In astronomy, degrees and minutes of arc are commonly used to describe the positions of stars, planets, and other celestial bodies in the sky or to measure the distance between celestial bodies.

 

Light year:

A light year is the distance that light can travel in the vacuum of space within one year. Since light travels at a speed of about 300,000 kilometers per second, one light year is equivalent to about 9.46 trillion kilometers.

The concept of the light year is often used to measure distances in space because the distances in space are often so great that conventional units of measurement such as kilometers or miles are not sufficient. For example, the distance to the nearest star system, Alpha Centauri, is about 4.37 light-years. This means that the light we see today from Alpha Centauri was emitted 4.37 years ago.

Is this really what space looks like in this clip?

The image is a color composite, which means that different color photographs and data of the cutout were put together. The American Judy Smith has put together the data from several telescopes for this picture:

  • Red and blue from infrared images of the Spitzer Space Telescope 
  • Green from data from WISE telescope 

By combining these data, astrophysical structures such as dust clouds (e.g., top left) or remnants of supernova explosions (e.g., bottom right) could be visualized. 

The white elements of the image are visible radio beams in the sky, at a frequency of 1.28 GHz (corresponding to a wavelength of 19 cm). These data were observed and recorded with the new MeerKAT radio telescope in South Africa. MeerKAT is a precursor to the international "Square Kilometre Array" (SKA) currently in planning.
The Square Kilometre Array (SKA) is a planned radio telescope project that will consist of thousands of antennas and is expected to be the largest and most sensitive radio telescope in the world. It will be built at two sites - in South Africa and in Western Australia.

The development of data processing techniques for the use of the MeerKAT radio telescope will be carried out at the Astronomical Institute of the Ruhr-Universität is funded by the BMBF.

Where does the radiation that is visible in white come from?

The radio radiation shown here comes primarily from electrons moving at almost the speed of light in the interstellar magnetic field. The fine filamentary structures through which the magnetic field is made visible are striking here. These electrons are part of the so called "cosmic rays". The origin and propagation of this particle radiation is studied at the Ruhr-Universität in the Collaborative Research Center 1491 of the DFG on the topic "The Interplay of Cosmic Matter - from Source to Signal".

Can you see the center of our galaxy in the picture?

Yes, the center of our Milky Way with the supermassive black hole is found in the white "overexposed spot" in the center of the image.

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