Par­al­lax pin­points Milky Way’s far side

Sky at Night Magazine - - BULLETIN -

The long­est dis­tance mea­sure­ment ever taken within our Galaxy has been achieved by the Very Long Base­line Ar­ray (VLBA), a network of 10 ra­dio an­ten­nas across the globe to cre­ate one gi­ant scope.

The read­ings pin­pointed that a star-form­ing re­gion on a dis­tant spi­ral arm is 66,000 lightyears away. Astronomers used par­al­lax mea­sure­ments, cal­cu­lat­ing dis­tance by mea­sur­ing the ap­par­ent shift in sky po­si­tion of a ce­les­tial ob­ject when ob­served from dif­fer­ent lo­ca­tions on Earth. “This means that, us­ing the VLBA, we can now ac­cu­rately map the whole ex­tent of our Galaxy,” says Al­berto Sanna, of the Max-Planck In­sti­tute for Ra­dio As­tron­omy.

Pre­vi­ous ef­forts to map the Milky Way have been ham­pered by dif­fi­cul­ties in mea­sur­ing the lo­ca­tion of ob­jects on the far side of our Galaxy.

“Most of the stars and gas in our Galaxy are within this newly-mea­sured dis­tance from the Sun. With the VLBA, we now have the ca­pa­bil­ity to mea­sure enough dis­tances to ac­cu­rately trace the Galaxy’s spi­ral arms and learn their true shapes,” says Sanna.­cil­i­ties/vlba

Star-form­ing re­gion The Sun The star-form­ing re­gion mea­sured is about as far away from the So­lar Sys­tem as you could get

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