Smallest spherical planet so far found
A new image of the asteroid Hygiea has revealed that this main belt object is actually spherical, making it the smallest spherical asteroid so far discovered and suggesting that it could be defined as a planet.
The image, taken by the Very Large Telescope (VLT) in Chile, is to the right. The asteroid was first discovered in 1849 and is the fourth largest in the asteroid belt, after Ceres, Pallas, and Vesta, with a diameter of 267 miles.
The image once again challenges the definition of what makes a planet. It also makes difficult the vague term “dwarf planet.” At what point does a dwarf become a full planet? This has never been clarified, which is why I tend to avoid using the term dwarf planet.
In my many interviews of planetary scientists, they generally dismiss the IAU’s poor definition of a planet and define a planet as anything that has settled into a spherical shape. In the case of Hygiea, that seems to apply.
Now available in hardback and paperback as well as ebook!
From the press release: In this ground-breaking new history of early America, historian Robert Zimmerman not only exposes the lie behind The New York Times 1619 Project that falsely claims slavery is central to the history of the United States, he also provides profound lessons about the nature of human societies, lessons important for Americans today as well as for all future settlers on Mars and elsewhere in space.
Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space, is a riveting page-turning story that documents how slavery slowly became pervasive in the southern British colonies of North America, colonies founded by a people and culture that not only did not allow slavery but in every way were hostile to the practice.
Conscious Choice does more however. In telling the tragic history of the Virginia colony and the rise of slavery there, Zimmerman lays out the proper path for creating healthy societies in places like the Moon and Mars.
“Zimmerman’s ground-breaking history provides every future generation the basic framework for establishing new societies on other worlds. We would be wise to heed what he says.” —Robert Zubrin, founder of founder of the Mars Society.
All editions are available at Amazon, Barnes & Noble, and all book vendors, with the ebook priced at $5.99 before discount. The ebook can also be purchased direct from my ebook publisher, ebookit, in which case you don't support the big tech companies and I get a bigger cut much sooner.
Autographed printed copies are also available at discount directly from me (hardback $24.95; paperback $14.95; Shipping cost for either: $5.00). Just email me at zimmerman @ nasw dot org.
A new image of the asteroid Hygiea has revealed that this main belt object is actually spherical, making it the smallest spherical asteroid so far discovered and suggesting that it could be defined as a planet.
The image, taken by the Very Large Telescope (VLT) in Chile, is to the right. The asteroid was first discovered in 1849 and is the fourth largest in the asteroid belt, after Ceres, Pallas, and Vesta, with a diameter of 267 miles.
The image once again challenges the definition of what makes a planet. It also makes difficult the vague term “dwarf planet.” At what point does a dwarf become a full planet? This has never been clarified, which is why I tend to avoid using the term dwarf planet.
In my many interviews of planetary scientists, they generally dismiss the IAU’s poor definition of a planet and define a planet as anything that has settled into a spherical shape. In the case of Hygiea, that seems to apply.
Now available in hardback and paperback as well as ebook!
From the press release: In this ground-breaking new history of early America, historian Robert Zimmerman not only exposes the lie behind The New York Times 1619 Project that falsely claims slavery is central to the history of the United States, he also provides profound lessons about the nature of human societies, lessons important for Americans today as well as for all future settlers on Mars and elsewhere in space.
Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space, is a riveting page-turning story that documents how slavery slowly became pervasive in the southern British colonies of North America, colonies founded by a people and culture that not only did not allow slavery but in every way were hostile to the practice.
Conscious Choice does more however. In telling the tragic history of the Virginia colony and the rise of slavery there, Zimmerman lays out the proper path for creating healthy societies in places like the Moon and Mars.
“Zimmerman’s ground-breaking history provides every future generation the basic framework for establishing new societies on other worlds. We would be wise to heed what he says.” —Robert Zubrin, founder of founder of the Mars Society.
All editions are available at Amazon, Barnes & Noble, and all book vendors, with the ebook priced at $5.99 before discount. The ebook can also be purchased direct from my ebook publisher, ebookit, in which case you don't support the big tech companies and I get a bigger cut much sooner.
Autographed printed copies are also available at discount directly from me (hardback $24.95; paperback $14.95; Shipping cost for either: $5.00). Just email me at zimmerman @ nasw dot org.
From the looks of things, it must be close to the point where there isn’t enough mass to cause enough gravity to result in a spherical object. Perhaps when we determine that we will know the lower limit of a “planet”
Hi Bob
This article
https://newatlas.com/space/large-asteroid-hygiea-dwarf-planet/
Mentioned the IAU requirements for planet and dwarf planet
For both
Orbit the sun
Large enough to have coalesced into a spherical shape
Not a moon
To be a planet and not a dwarf planet
Cleared its orbit of debris
Chris: I am well aware of the IAU’s definition. I also know that it makes no sense, and is worthless. And all my comments are reinforced by what planetary scientists have told me.
Looks a little like the Death Star.
Everything round is a planetoid.
Call something a sun if it gives off detectable light.
Call something a planet if it is a planetoid and it orbits a sun.
Call something a moon if it orbits a planet.
Other objects can have names like asteroids or comets or pretty much anything you like.
Call something a moon if it orbits a planet.
Should be
Call something a moon if it is a planetoid and it orbits a planet.