
Scientists Are Just Starting to Understand Earth’s Eighth Continent, Zealandia - dskrvk
http://www.atlasobscura.com/articles/zealandia-continent-expedition-new-zealand-cores-tectonics
======
jessriedel
Several commenters on _semantics_ in this thread (e.g.,
[https://news.ycombinator.com/item?id=15473604](https://news.ycombinator.com/item?id=15473604)
,
[https://news.ycombinator.com/item?id=15473705](https://news.ycombinator.com/item?id=15473705)
,
[https://news.ycombinator.com/item?id=15473402](https://news.ycombinator.com/item?id=15473402)
) seem to be missing the key empirical fact: that the Earth's crust comes in
two distinct types: oceanic crust
([https://en.wikipedia.org/wiki/Oceanic_crust](https://en.wikipedia.org/wiki/Oceanic_crust))
and continental crust
([https://en.wikipedia.org/wiki/Continental_crust](https://en.wikipedia.org/wiki/Continental_crust)).
More specifically, the distribution of crust density (and other properties) is
_bimodal_ due to being caused by distinct formation processes. The
presence/lack of ocean water on top of a location on Earth is a consequence,
not cause, of the crust type. This is why the continents are clearly visible
on the Earth's topographical map without water. Otherwise, you'd expect the
visible shape of the continental land masses to be highly dependent on the
exact waterline, which is mostly not the case.

So sure, popular media is often framed around silly terminology changes, but
this does not mean that calling Zealandia a continent fails to have real
empirical meaning, or detract from the fact that Zealandia _is_ unusual in
being continental crust largely covered by water. Likewise, removing Pluto
from the list of planets reflected the empirical fact that Pluto is
qualitatively different than the other planets, and qualitatively similar to
the other dwarf planets.

~~~
nostrademons
I think most of the semantic objections to the article's title are about it
being earth's _eighth_ continent, rather than earth's eighth _continent_. If
you're going by the tectonic plate definition, Eurasia is one continent
(there's no distinct plate boundary between them), while India, Somalia,
Arabia, Madagascar, the African Great Lakes, and much of Southeast Asia are
all distinct continents.

~~~
scythe
I think the criterion is " _mostly_ contiguous region of continental crust",
in which case the separation between Africa and Asia _might_ separate them,
and the separation between the Americas similarly _might_ ; according to
purely topological definitions there are precisely four continents (Americas,
Eurasia/Africa, Australia, Antarctica and maybe Greenland). Tectonic plates
don't correspond to very much from a geographic perspective -- Baja California
would become _two_ new continents, one of which groups it with the South
Island of New Zealand.

~~~
ThrustVectoring
The continental distinctions as they are is pretty much geopolitics. There's
no passable land route between North and South America, because the connection
is through thick jungle. Similarly, pretty much nobody wants to go through the
Ural mountains to go overland from Europe to Asia. Since little overland
commerce or credible overland invasion routes exist between continents, they
can be thought of mostly independently.

~~~
ulucs
Why pass through Ural mountains when you could just pass through a bridge?

------
thx4allthestuff
As I've grown older, I've come to find peace in letting go of semantics. Is it
a dwarf planet, or is it a planet? I'm content simply pointing at the things
that I recognize and saying, "There is that thing. Whatever the kids /
scientists are calling it these days. I know a lot about that thing, but
perhaps not it's name."

~~~
Jach
Or as Feynman put it, Names Don't Constitute Knowledge:
[https://youtu.be/lFIYKmos3-s](https://youtu.be/lFIYKmos3-s)

------
vorg
8 continents? I guess that's Europe, Asia, Africa, North America, South
America, Australia, Antarctica, and Zealandia.

But I see:

* 1 mega-continent, i.e. Eurasia, which has sub-continents Europe and India tacked on

* 3 normal continents, i.e. Africa, North America, South America

* 3 "dwarf" continents, i.e. Australia, Antarctica, Zealandia

Not only are those 3 dwarf continents far smaller than the others, but one's
covered with sand, another with ice, and the other with water.

~~~
rhn_mk1
If we're talking geology, then we might as well look at the tectonic plates
[0][1].

\- 14 or 15 major plates

\- 38 small plates

Yet people will talk about 5-7 continents all the time.

Because people will be confused no matter which ill-defined definition is
used, I'm switching to the botanical one [2] with 9. It seems to at least have
some practical value.

[0]
[https://en.wikipedia.org/wiki/Continental_plate](https://en.wikipedia.org/wiki/Continental_plate)

[1]
[http://peterbird.name/publications/2003_PB2002/2003_PB2002.h...](http://peterbird.name/publications/2003_PB2002/2003_PB2002.htm)

[2]
[https://en.wikipedia.org/wiki/Continent#Botanical_continents](https://en.wikipedia.org/wiki/Continent#Botanical_continents)

~~~
derefr
I presume a lot of those plates are ignored because they're entirely
underwater.

~~~
k__
If you leave the underwater parts out, you get a reasonable amount of
continents. Sure Arabia and India would confuse people a bit, but besides them
it seems to map well to what people expect.

------
kilovoltaire
It seems like tectonic plates are less arbitrarily defined than continents.

[https://en.wikipedia.org/wiki/List_of_tectonic_plates](https://en.wikipedia.org/wiki/List_of_tectonic_plates)

------
jpollock
Nothing like discovering a new continental shelf when an underwater mining
gold rush is about to start.

------
ihm
All the semantic arguments here would disappear if we all simply recognized
the "set of continents" for what it really is: a set-valued sheaf on some
parameter space ([https://xorshammer.com/2016/07/24/the-cgp-grey-topos-of-
cont...](https://xorshammer.com/2016/07/24/the-cgp-grey-topos-of-
continents/)).

------
goodcanadian
Zealandia, while interesting in many ways, doesn't come close to meeting my
definition of a continent. I wish they would stop calling it that.

~~~
justinator
Well, plate tectonics is what, a 70 year old theory, at best? In the 1950's,
it wasn't generally believed that continents _moved_.

So, I think the definition of what is, and what is not a continent is
generally... fluid at this point.

See also: definition of a planet. How can you define what a planet is, if you
keep discovering new ones, that don't quite fit the old definition? Pluto was
"discovered" < 100 years ago.

I remember being taught in school that there was only three kingdoms of life!

Science! It changes. And that's a good thing.

~~~
goodcanadian
Sure, the definition of a continent is somewhat subjective and subject to
change, but in my personal opinion, continents are large land masses.
Zealandia fails on two counts:

a) It is much too small. b) It is underwater.

The fact that it was at one time above sea level is not particularly relevant
in this discussion. Much of the Mojave desert used to be underwater. Does that
mean it is currently a sea?

~~~
smhost
> in my personal opinion, continents are large land masses

The point is that your personal opinion is badly formed. Your definition of a
continent is almost completely useless, which is obvious when you just look at
a map. How large is "large"? Is Greenland its own continent? How do you
classify Indonesia?

The new definition at least makes sense. It updates the word's meaning to
reflect a more scientifically literate understanding of continent formation.

~~~
goodcanadian
There is a new definition? Pushing Zealandia as a continent is mostly just the
opinion of one group of researchers. Granted their opinion may be more valid
than mine in this matter, I don't see that there is yet a general consensus
that I'm fighting against.

You are right, of course, that the term is poorly defined and not very useful.
It is defined mostly by convention and somewhat inconsistently. I don't
believe that Greenland is generally considered to be a continent by anyone nor
any of the islands in Indonesia. In my mind, even Australia is borderline, but
it is generally considered to be a continent. Anyway, my point was that
Zealandia is so far outside the conventional definition of a continent that it
is not useful to call it that. I realize not everyone will agree with me, and
I would be less annoyed if people were to refer to it as "A submerged
continent" rather than "THE eighth continent."

All that said, I've spent far more words on the subject than it is worth; I
really don't care as much as it probably appears. I'm really only taking issue
with your assertion that my _" personal opinion is badly formed."_

~~~
smhost
Yeah, same, I don't really care either. What actually bothers me is the
concept that your personal opinion is a sufficient justification for
perpetuating the status quo, regardless of the rigor of reasoning behind the
proposal for the redefinition.

I like your second comment a lot better. I agree that calling it a submerged
continent is much better than just calling it a continent.

------
bitwize
Wow, it really is a lost continent, like Mu, or Hyrule from _Wind Waker_.

As I keep saying, the world is a strange and pretty awesome place.

------
red5tar
This is quite the extraordinary discovery.

------
forkLding
So we now have 8 continents and 8 planets? Just making sure my scientific
knowledge is up-to-date.

~~~
umanwizard
It's not clear to me that there is a rigorous definition of "continent", since
different cultures enumerate them differently.

For example, in the US, North America and South America are counted
separately, whereas in many cultures "America" is one continent (and, a
related issue is that many people in Latin America would consider the US and
Canada and NOT Mexico as part of "North America"). Also in some cultures
Europe and Asia are separate, and in some they are one continent.

~~~
KGIII
When this first cropped up, I asked a few geologists and not even they know
what a continent is. As near as I could tell, they preferred we stop using the
term.

------
nether
Granted, the definition of "continent" is not rigorous, and depending on where
you grew up in the world, you might have learned there are 5-7 "continents."

------
exabrial
Here I thought it was the Island of Sealand...

