Dear exoplanet freaks:

 

Even our galaxy is an outlier.

How weird is the Milky Way?

Astronomy.com 7/04/25

As is our solar system

(Two gas giants in the outer portion)

and our planet.

(Abundance of water, atmosphere etc.)

Sheer volumes of #'s of anything?

(Stars etc)

DOESN'T MEAN ANYTHING.

Get a clue.

"Placing the Milky Way’s uniqueness, or lack thereof, in a broader context is crucial because, for decades, scientists have used it as a model to understand how galaxies form and evolve."

(So what if they used the wrong model for decades?)

"Around 10 years ago, Marla Geha at Yale University and Risa Wechsler at Stanford University launched an ambitious effort to answer this question. Their approach involved looking not only at galaxies themselves, but also their entourages of dwarf galaxies — satellite galaxies that orbit their larger hosts. Because dwarf galaxies are smaller, they are more sensitive to their environment and can act as probes. Studying them can yield insights into their host galaxies’ invisible halos of dark matter and how they evolved."

"The decade-long effort has now mapped 101 Milky Way analogues in the distant universe, and 378 of their respective satellites. The team’s results suggest that while our galaxy is far from a cosmic anomaly, its satellite galaxies do sport distinct traits that make the Milky Way something of an outlier compared to its peers."

"When scientists attempt to re-create Milky Way-like systems in computer simulations, even the best models struggle to perfectly replicate this swarm of dwarf galaxies orbiting our galaxy. This has led astronomers to worry whether the Milky Way — their primary benchmark — accurately captures the broader population of galaxies and their faint satellite galaxies."

(Kinda hard to get an accurate measurement when you not using the correct measuring device, which is what scientist just mighthave been doing.)

“If I have a small sample, is it representative of the population as a whole?”

 Andrew Wetzel of University of California, Davis

"The survey’s first significant result, published in 2017, reported satellite galaxy populations around just eight Milky Way analogues. But already, the team was beginning to see that our galaxy and its collection of satellite galaxies was not typical of other galaxies in the sample. With the exception of the Magellanic Clouds, the Milky Way’s dwarf satellites have all stopped forming stars for a billion years or more — a state that astronomers call quenched. But of the 27 dwarf galaxies the SAGA team identified orbiting other galaxies, all but one were still actively forming stars."

"By 2021, the SAGA collection of host galaxies had grown to 36, and the trend continued. In 2024, the team published their most recent results in The Astrophysical Journal, bringing their count to just over 100 host galaxies."

"These results show that our galaxy’s mix of satellites is relatively uncommon. The Milky Way’s swarm of dead, quenched dwarf galaxies stands in stark contrast to satellites of Milky Way-like galaxies in the distant universe, most of which are still birthing new stars."

"Possibly, the Milky Way is peculiar in that it acquired most of its satellites earlier in its history than similar galaxies."

"Another unique factor in the evolution of the Milky Way and its satellites could be that our galaxy has a close neighbor, the Andromeda Galaxy (M31). These two major galaxies could be influencing each other’s satellite systems in ways that set them apart from other host galaxies in the SAGA survey, says Nadler."

"At this point, doubling or tripling the number of Milky Way analogues — which could take a decade — doesn’t actually teach a whole lot more, says Geha. To be truly revolutionary, the number of analogues would need to increase by at least a factor of 10, a feat that will require next-generation technology."