How Markarian 205 nearly broke the universe: This Week in Astronomy with Dave Eicher

Markarian’s Chain types the core of the Virgo galaxy cluster. Credit score: Katelyn Beecroft

NGC 4319 and Markarian 205 are a pair of objects with loads of lore and historical past. NGC 4319 is a spiral galaxy about 77 million light-years distant, whereas Markarian 205 is a quasar — a particularly luminous energetic galaxy — about 1 billion light-years away. We all know these distances due to measurements of those objects’ redshifts. As a result of growth of the universe, the farther a galaxy is from us, the sooner it seems to recede from us, and the extra stretched (or purple) its mild waves are once they attain us.

However within the Seventies, the astronomer Halton Arp turned satisfied that there was a lightweight bridge connecting NGC 4319 and Markarian 205. He believed that Markarian 205 was initially the galactic core NGC 4319, and had been ejected from it. This is able to indicate that the objects lay on the similar distance, regardless of that the truth that their redshifts indicated Markarian 205 was over a dozen occasions extra distant. If there was a real bodily connection between the 2 objects, it will imply that measurements of distant galaxies based mostly on their redshift weren’t dependable.

Arp’s assertions provoked a debate that raged for 20 years. Ultimately, the Hubble House Telescope performed a key function in resolving the matter: Whereas Markarian 205 does seem contained in the outer spiral arms of NGC 4319, Hubble might additionally see that sure wavelengths of sunshine from the quasar have been being absorbed by NGC 4319, proving that it does certainly lie within the background.