Gas Cloud Wrapped in Dark Matter Is Like a Speeding Cosmic Burrito
Wrapped in dark matter, an object known as the Smith Cloud is hurtling toward the Milky Way at more than 150 miles per second. Now 8,000 light-years away, the gassy clump of hydrogen is expected to smash into the galaxy in about 30 million years.
But that won’t be the first time this blob of gas has met our galaxy: Scientists think it’s been here before, millions of years ago.
Normally, gas clouds don’t easily survive such encounters without being torn apart; to make it through, a cloud would need to be incredibly dense. Smith’s Cloud is not.
Astronomers initially proposed that the cloud’s strong magnetic field could shield it during its galactic passage. But new observations, made using the National Radio Astronomy Observatory’s Green Bank Telescope, offer another suggestion for how the Smith Cloud endures. Like a cosmic burrito, the cloud is wrapped in dark matter — the mysterious substance thought to comprise more than 80 percent of the matter in the universe. That dark shell protects the cloud from being shredded by the Milky Way (though it does appear to have a tail, like a comet, containing material that’s being sucked up by the galaxy).
Since interstellar clouds don’t usually come gift-wrapped, scientists now suspect Smith’s Cloud could be the gassy remains of a failed dwarf galaxy that never grew up and turned on its stars.
Related Topics
Go Further
Animals
- How can we protect grizzlies from their biggest threat—trains?How can we protect grizzlies from their biggest threat—trains?
- This ‘saber-toothed’ salmon wasn’t quite what we thoughtThis ‘saber-toothed’ salmon wasn’t quite what we thought
- Why this rhino-zebra friendship makes perfect senseWhy this rhino-zebra friendship makes perfect sense
- When did bioluminescence evolve? It’s older than we thought.When did bioluminescence evolve? It’s older than we thought.
- Soy, skim … spider. Are any of these technically milk?Soy, skim … spider. Are any of these technically milk?
Environment
- Are the Great Lakes the key to solving America’s emissions conundrum?Are the Great Lakes the key to solving America’s emissions conundrum?
- The world’s historic sites face climate change. Can Petra lead the way?The world’s historic sites face climate change. Can Petra lead the way?
- This pristine piece of the Amazon shows nature’s resilienceThis pristine piece of the Amazon shows nature’s resilience
- Listen to 30 years of climate change transformed into haunting musicListen to 30 years of climate change transformed into haunting music
History & Culture
- Meet the original members of the tortured poets departmentMeet the original members of the tortured poets department
- Séances at the White House? Why these first ladies turned to the occultSéances at the White House? Why these first ladies turned to the occult
- Gambling is everywhere now. When is that a problem?Gambling is everywhere now. When is that a problem?
- Beauty is pain—at least it was in 17th-century SpainBeauty is pain—at least it was in 17th-century Spain
Science
- Here's how astronomers found one of the rarest phenomenons in spaceHere's how astronomers found one of the rarest phenomenons in space
- Not an extrovert or introvert? There’s a word for that.Not an extrovert or introvert? There’s a word for that.
- NASA has a plan to clean up space junk—but is going green enough?NASA has a plan to clean up space junk—but is going green enough?
- Soy, skim … spider. Are any of these technically milk?Soy, skim … spider. Are any of these technically milk?
Travel
- Could Mexico's Chepe Express be the ultimate slow rail adventure?Could Mexico's Chepe Express be the ultimate slow rail adventure?
- What it's like to hike the Camino del Mayab in MexicoWhat it's like to hike the Camino del Mayab in Mexico