Author Archives: Ivan Semeniuk

Supernova remnant Cassiopeia A

Supernova Mystery Solved

Is there a neutron star lurking at the heart of the spectacular supernova remnant or something much weirder? A new analysis of observations suggests a surprising answer.

Hints of "dark matter"?

Is Fermi Seeing Dark Matter?

A new analysis showing a cloud of high-energy particles hovering around the center of the Milky Way could be the signature of dark matter and evidence of a “dark force”, but not everyone is convinced.

event horizon silhouette

How To See a Black Hole

Surprising advances in radio astronomy have put astronomers within reach of imaging the supermassive black hole in the Milky Way and the active galaxy M87.

Podcast: Saving Mt. Wilson

What do you do when a wildfire threatens to engulf your observatory? In the latest episode of The Universe in Mind podcast Hal McAllister tells the story of the battle to save Mt. Wilson. Author Marcia Bartusiak puts the famous observatory in context with her new book about the discovery of the modern universe.

Can Magnetism Save a Vaporizing Planet?

The "hot Jupiter" HD 209458b caused a sensation when astronomers seemed to see its gaseous atmosphere leaking out into space. Now one team of researchers says a magnetic personality could prevent the planet from evaporating before our eyes.

Mammoths on the march

Podcast: An Ice-Age Impact?

Just under 13,000 years ago, the mammoth and several other large mammalian species vanished from North America. In a podcast, Ivan Semeniuk explores the controversial claim that the mass extinction was triggered by a comet impact and how microscopic diamonds hold the key to understanding what really happened.

A Megascope for Hawaii

There was a certain amount of politics behind the decision to site the Thirty Meter Telescope on Mauna Kea. But there was science behind the politics too.

From Venus to Gaia… and back down to Earth

One of the many big differences between Earth and Venus that could have a bearing on habitability is the absence of a strong magnetic field on Venus. So is it just dumb luck that we have a magnetic field and Venus doesn’t? Or is something deeper going on here?