31
votes
What are these undersea lines all around Hawaii?
Short answer: The lines radiating from the island are artifacts from a mapping process that superimposes high-resolution sonar data from standard ship tracks on top of r low- or average sonar data ...
- 3,474
27
votes
Accepted
How old is the Earth?
Yes, the age of the Earth is about 4.5 billion years (4,500 million years). Your linked articles describes well how it was formed and how we know about it. The uncertainty is less than 1% and depends ...
- 5,936
26
votes
Accepted
Does the Plate tectonics contradict the theory of continental drift?
The boundary between the African and South American plate is a 'divergent' boundary. The two continents were joined as part of the Pangean super-continent. In the Cretaceous period a rift opened up ...
- 2,010
24
votes
Accepted
What is the fastest the Earth has ever spun?
The speed of rotation of Earth is controlled by its angular momentum. And the conservation of angular momentum is a very serious law of physics (perhaps even stricter than conservation of mass). So in ...
- 17.6k
23
votes
Why had climate change not been proven beyond doubt for so long?
It's the first very significant report to make that claim because the claim is unscientific in nature.
As Albert Einstein once said:
The scientific theorist is not to be envied. For Nature, or more
...
- 377
19
votes
Accepted
When did wildfires start to occur on earth?
A definitive statement comes from the abstract of Scott and Glasspool1, 2006:
Charcoal, a proxy for fire, occurs in the fossil record from the Late Silurian (≈420 Myr) to the present.
One of the ...
- 3,548
18
votes
Does the Plate tectonics contradict the theory of continental drift?
Alfred Wegener developed his theory of continental drift in the early 20th century. His theory wasn't well accepted at that time. Geologists of that time had their own not quite scientific ideas ...
- 23.1k
17
votes
Accepted
Why had climate change not been proven beyond doubt for so long?
Chapter 9 of the Fourth Assessment Report gives a comprehensive overview of the difficulties involved in 'detection and attribution'. It is worth reading in detail - it gives a much better idea of the ...
- 186
16
votes
If we assume the mega impact hypothesis for the formation of Moon, where on Earth is the impact point?
I think you are confused about the timescales and the magnitude of the impact that is being talked about here.
The collision between the early Earth and a roughly Mars sized body, Theia is thought to ...
- 2,221
15
votes
What significant factors influencing geological change are still occurring?
The effects of Earth's past climate variations on the landscape, especially glaciation, cannot be underestimated.
The multiple glacial advances and retreats over the last 4 million years or so have ...
- 3,548
15
votes
Why had climate change not been proven beyond doubt for so long?
Just because a "small number" of scientists knew about something in the mid 1820s doesn't mean it was initially accepted by other scientists. You also have to consider the means of ...
- 24.6k
14
votes
Accepted
What would it be like to live in an ice age?
It depends where, the continental landmasses at higher latitudes would be covered by massive ice sheets. Therefore the life in the sections of the US and Europe that are close to the Ice sheets would ...
- 17.6k
14
votes
Could the earth be much older than the currently accepted number?
The age of the solar system is 4.6 billion years. We know that because almost all meteorites are 4.6 billion years old¹. Therefore, that puts a very solid upper boundary to the age of the Earth.
...
- 11.6k
13
votes
Accepted
Water on Mars and Earth
If water on Earth came from meteorites, why doesn't Mars have substantial water?
First off, that's a conjecture regarding the origin of the Earth's water rather than a known fact. A few times a year ...
- 23.1k
12
votes
Is this scientific explanation of The Bible flood accurate?
Fishing through the links mentioned over at Christianity SE, I netted this scientific paper about freshwater and marine fish: Why are there so few fish in the sea?. Apparently the bulk (96%) of marine ...
- 1,207
12
votes
Why is Earth's Core Iron?
I can only answer the question of why is it mostly iron. Not too sure of the magnetic properties of iron versus nickel.
As said in another answer, there is simply much more iron around than nickel. ...
- 23.1k
12
votes
Accepted
Pangaea - Why did all the land mass form in one area?
The formation and break up of supercontinents have happened throughout Earth's history in almost a cyclical manner. There may have been many others supercontinents before Pangaea and the total number ...
- 15.4k
11
votes
Accepted
Is there likely to be coal under the Sahara?
The older rocks underlying the Sahara
are mostly granite, schist, or gneiss, all mixtures of igneous and metamorphic rocks forged deep beneath the surface
This stable mass of rock has been covered ...
- 24.6k
11
votes
What are these undersea lines all around Hawaii?
Hawai was created by a coat of plume. This means that hot material rises and penetrates the oceanic currents! These are fracture marks from this process.
Secondly, the plate is torn apart by ...
- 1,906
10
votes
Accepted
For how long has the Earth been habitable for humans?
One needs breathable air, drinkable water, and food to survive. Food as we know it was nonexistent prior to the Ediacaran, which began about 635 million years ago. Life was exceedingly primitive (...
- 23.1k
10
votes
Accepted
If Earth had rings would gravity exerted by Earth decrease?
Rings wouldn't decrease the gravity much, but the exact amount would depend on the exact geometry of the rings. One reason is that the gravity of one side of the ring would partially cancel the ...
- 17.6k
9
votes
Have there ever been any islands that disappeared due to rising sea level?
Definitely, there are lots.
As you say, sea-level is rising in most (but not all) coastal areas. Indeed, at the end of the last ice age ca. 12,000 years ago, sea-levels rose about 120 m. Many islands ...
- 11k
9
votes
Why is a future increase in solar luminosity by 10% supposed to have disastrous consequences for life on earth when the last 30% did not?
In this regard you can think that the Earth system is like a house with heating but no Air conditioning. Therefore, it has a powerful mechanism to stay warm when the solar illumination is weak (...
- 17.6k
9
votes
Does the Plate tectonics contradict the theory of continental drift?
"Continental Drift" was a theory developed to explain observed phenomena (the coastline of South America and Africa being but one example). Plate tectonics, on the other hand, is the ...
- 191
8
votes
What is the age of the earth's oil?
Oil can be generated from pretty much anything organic. The oldest oil that I know of comes from a porous Eocambrian siltstone in the Sultanate of Oman. This was formed nearly 200 million years before ...
- 14.2k
8
votes
A circle shape in Madagascar
It is an extinct volcanic crater.
The location is not listed as one of the active volcanoes in Madagascar.
Simplified geologic map of Madagascar (reference) shows the crater to be mapped as basaltic /...
- 5,959
8
votes
Are we entering a new Ice Age according to Milankovitch cycles?
It thus seems reasonable to say we are entering another Ice Age according to Milankovitch cycles.
Some of the Milankovitch conditions would appear to make the Earth ripe for a new glacial epoch ...
- 23.1k
7
votes
Why is Earth's Core Iron?
The main reason that there is more iron than nickel in the Earth's core, and in the universe generally, is that Nickel-56 beta-decays to Iron-56 (via cobalt-56).
Much nickel-56 forms in Asymptotic ...
- 5,962
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