A sense of scale

This striking photograph from Yuri Beletsky captures many wonders — both terrestrial and astronomical — across an incredible distance scale.

In the immediate foreground looms ESO’s VISTA survey telescope. This 4.1-metre telescope scans the skies in infrared light, picking out astronomical objects of interest so that they can be studied by the four 8.2-metre Unit Telescopes of ESO’s Very Large Telescope (VLT) facility. This facility can be seen on the mountaintop to VISTA’s right, about a kilometre up the road.

In the sky above VISTA a luminous and dark-ribboned band runs from lower left to top right. This is the disc of the Milky Way, seen edge-on and looking inward toward the galactic core. Although we cannot see all the way to the core with our unaided eyes, we have gauged its distance as about 30 000 light-years from us. That distance works out as about 280 quadrillion kilometres, or 280 000 000 000 000 000 trips up the road from VISTA to the VLT!

The glowing blob seen here almost directly overhead of the VLT is the Large Magellanic Cloud (LMC), a dwarf galaxy that neighbours the Milky Way. It is about 160 000 light-years away. Below and slightly to the left of the LMC is another diffuse brightness in the sky, the Small Magellanic Cloud (SMC). This galaxy is nearly 200 000 light-years away meaning that, walking at five kilometres an hour, the journey to the SMC would take more than 43 trillion years.