Author Archives: Johannes Hirn

GM Aur

Planetary Preemies?

Protoplanetary disks around three young stars turn out to have large central holes, which were presumably cleared by still-growing Jupiter-mass planets. But there’s a problem: the stars are too young.

NGC 3621 Spitzer Chandra

Black-Hole Missing Link Found?

Astronomers are searching galaxies with no central bulges for intermediate-mass black holes — the missing links between the small black holes that result from collapsing stars and the monsters in the cores of bulge galaxies. A team reports that it's found one — or maybe three.

Galaxy IC 2497 and the Voorwerp in  real colors, as imaged by the William Herschel Telescope in La Palma, Canary Islands, Spain.

A Now-You-See-It, Now-You-Don’t Quasar?

Poring over sky-survey data, a Dutch schoolteacher noticed a starless blue-green blob near a faint galaxy. Astronomers think "Hanny's Voorwerp" is a cloud of intergalactic gas lit by an active galactic nucleus (AGN) hidden in the galaxy just to its north. But if so, why don't we see the AGN?

Alien Maps Fig 2

Exoplanet Mapping Tested on Earth

Researchers are developing a method to detect oceans and clouds on planets orbiting other stars. To test this idea, they aimed the telescope aboard NASA’s Deep Impact probe toward Earth, and made a rough map of our world.