On August 25, 2006, the International
Astronomical Union (IAU) took a deciding vote on the fate of Pluto as a planet.
That day, Pluto was demoted from being the ninth planet in our solar system to “dwarf
planet”. But as it happens, Pluto's fate was inextricably linked to an object
3% bigger than Pluto which was discovered by Dr. Mike Brown et al. in the
trans-Neptunian region known as the Kuiper belt, of which until then, Pluto was
the largest inhabitant.
The Kuiper belt was discovered in 1992. By
1997, almost a hundred bodies had been found. Suddenly the study of those
objects located beyond Neptune became a hot field in astronomy. Dr. Mike
Brown's search for a planet beyond Pluto started around that time, using,
initially, the 48-inch Schmidt telescope at Palomar Observatory in Pasadena,
California. His survey of the sky took two years and didn't yield the desired
result. He refers to that time as follows: “...I
talked to my friends about planets. I thought about names for new planets. I
gave lectures about the possibility of new planets. I did everything I could,
except finding new planets.” By 1999, about 500 bodies in the Kuiper belt
were known.
After three years of systematically surveying
the sky and writing computer code to process the images in the computer, the
searching had amounted to nothing, but by mid 2001, the photographic plates of
the 48-inch Schmidt telescope at Palomar Observatory were replaced by a modern digital
camera that was able to detect fainter things in the sky. Within months, Dr. Brown's
graduate student started finding things. In June 2002, they found an unusually bright
wandering object which they nicknamed “Object X”.
“Object X goes around the sun every 288 years in an orbit closer
to circular than even most of the planets, but it is tilted away from the
planets by 8 degrees.” Comparatively, Pluto,
considered the oddball among the (former nine) planets, orbits the sun in an
elongated, rather circular orbit, and unlike its (former) counterparts, it is
tilted in a 20° angle away from the rest—unlike the others which orbit the sun
in rather flat disks. Like on Pluto's, there is dirty ice on the surface of “Object
X”, and frozen methane, the latter “never
before seen anywhere in the Kuiper belt.”
Years later, a graduate student of Dr. Brown
would speculate that as Titan, Pluto and most of the objects in the Kuiper belt
“had formed with methane, but the
gravitational pull of Object X [being so small] was not quite strong enough to
hold on to the methane forever. With the Keck telescope...the last remnants of
frost on a cold dying world [had been observed].” “Object X” ended up being
half the size of Pluto, and was formally named Quaoar.
In the fall of 2003, the small telescope at
Palomar was fitted with a new super camera. Dr. Brown, suddenly working on his
own again, refined the computer software and discarded 10% of the sky in the
pictures to get rid of camera flubs. As potentially golden images became more
manageable, Dr. Brown began to find more unusually bright wandering objects.
Nothing significant, but it was a step in the right direction.
In November 2003, he found a faint object
that moved at half the speed of anything he had ever seen. Something more than
three times the distance of Pluto, with an extremely elongated orbit—it takes
11,000 years to go around the sun—, beyond anything seen thus far in the solar
system. The object was nicknamed The Flying
Dutchman, as the ship of folklore. Dr. Brown theorized that Dutch could have acquired its odd orbit
at the birth of the sun 4.5 billion years ago when stars just like ours
populated the sky, which “could have
pushed Dutch around and put it exactly where it is now...Dutch was not just a
chunk of ice and rock at the edge of the solar system. It was a fossil left
over from the birth of the sun.” Dutch
was officially named Sedna, after the
goddess of the sea in Inuit mythology. Sedna
was found to be three-quarters the size of Pluto.
Two days after Christmas in 2004, Dr. Brown
observed his brightest wandering object yet. He nicknamed it Santa in honor of the season. Its orbit was
elliptical and tilted, as objects in the Kuiper Belt have. After a lot of
controversy about its actual time, place, and team of discovery, it was
officially named Haumea after the
Hawaiian goddess of childbirth, a suitable name since “many objects in the outer solar system can now be traced back to
having originally been part of the surface of this object.” It has been
theorized that “early in the history of
the solar system, a much larger Haumea was smashed by another icy object in the
Kuiper belt travelling at something like ten thousand miles per hour...The
glancing blow left Haumea spinning faster than anything else in the solar
system.” Its two moons, chunks of Haumea,
were named Hi'iaka and Namaka. Haumea is covered in pure ice and is smaller than Pluto. It weighs
one-third as much as Pluto and its moon Hi'iaka
goes around it every forty-nine days.
Two weeks after the discovery of Santa (now Haumea), Dr. Brown discovered a brighter object still, four times
more distant than Pluto. It takes 557 years to go around the sun. It was
nicknamed Xena, after TV's warrior
princess. Its surface is covered in solid frozen methane, like Pluto's. It was
temporarily considered the tenth planet and it is one of the main reasons why
Pluto was demoted from planethood. It was officially named Eris, after the Greek goddess of discord and strife. Its moon was
called Dysnomia. Eris is 27% more massive than Pluto. “Since Pluto and Eris are nearly identical in size, the interior of
Eris must be made out of heavier material. In this part of the solar system,
the insides of bodies are almost entirely made up of rock and ice. Eris weighs
so much that it must be almost entirely rock, while Pluto has significant
quantities of frozen water hidden inside it.”
In April 2004, Dr. Brown found yet another wandering
object, brighter than any of the previous two. He nicknamed it Easterbunny. As Xena’s, its surface is like Pluto's, “covered with large amounts of almost pure
methane ice, a consequence of the fact that it is just a little smaller than
Pluto and lacks enough gravity to hold a substantial nitrogen atmosphere.”
Its official name became Makemake,
after the fertility god of the island of Rapa Nui (Easter Island).
Why I Killed Pluto and Why It Had It Coming by Mike
Brown is for the most part a science memoir of almost
a decade long search for trans-Neptunian objects of significance, now
denominated “dwarf planets” (for lack of a better term). His memoir also
details his initial steps in the dark as a young Caltech professor, meeting his
wife-to-be, how they romanced, married, and had a daughter.
Wow, that is a lot of science! I am glad you found it entertaining as well as instructional. I almost always find memoirs to be good reading.
ReplyDeleteIt sounds more science-y than it was. It was a lot of fun with plenty of laugh out loud moments.
DeleteIt sounds interesting. Pretty catchy title too. Does he write it for a wide public audience? -- or will it be too scientific for someone like me to understand? How did you find this one?
ReplyDeleteHe writes for a wider audience, and the science he talks about, he explains in a down to earth manner. I think anyone would enjoy it like I did.
DeleteI found it on Amazon while looking for another book; this one appeared among suggestions.
This sounds really fascinating. Thanks for bringing it to my attention.
ReplyDeleteYou're welcome, Dorothy! :-)
DeleteSounds interesting :)
ReplyDeleteIt was.
DeleteTo be fair it's probably not a book I'd pick up but you did a great review and I'm glad you enjoyed it.
ReplyDeleteLynn :D
Thanks, Lynn. I know it's not everyone's cup of tea, but it's mighty entertaining.
Delete