Is the Earth's core hotter than lava?
In the core, the process of nuclear fusion creates temperatures of approximately 27,000,000° F. A temperature of 27 million degrees Fahrenheit is more than 12,000 times hotter than the hottest lava on Earth! If the core is the hottest part of the sun, what's the coolest part?
That led to the conclusion that the temperature of the center of the Earth is about 6000 degrees Celsius - a temperature about 9% higher than what exists on the surface of the Sun.
The inner core is solid because it is made of very dense, or heavy, materials - like iron and nickel. Even though it is very hot, these materials don't "melt" very easily, so they stay solid.
Notice that the photosphere actually has a temperature quite close, or even a bit colder, than the Earth's core! However, outside the photosphere there is the Sun's corona, which can reach temperatures as high as 17,000,000 K; this is hotter than the center of the Sun, and is the hottest place in the solar system!
A return stroke of lightning, that is, a bolt shooting up from the ground to a cloud (after a stream of electricity came downward from a cloud) can peak at 50,000 degrees Fahrenheit (F). The surface of the sun is around 11,000 degrees F.
And the answer: lightning. According to NASA, lightning is four times hotter than the surface of the sun. The air around a stroke of lightning can peak at 50,000 degrees Fahrenheit, while the surface of the sun is around 11,000 degrees. Meanwhile, magma can reach temperatures near 2,100 degrees.
Four billion years from now, the increase in Earth's surface temperature will cause a runaway greenhouse effect, creating conditions more extreme than present-day Venus and heating Earth's surface enough to melt it. By that point, all life on Earth will be extinct.
The Earth's core does, in fact, cool down over time, and eventually it will solidify completely. Since the Earth's magnetic field (which protects the atmosphere and biosphere from harmful radiation) is generated by molten iron in the core, the solidification of the core might seem quite foreboding.
In a word, no. The center of the Earth is roughly 3,959 miles (6,371 km) down. The deepest hole that was ever drilled was the Kola Superdeep Borehole, at 7.6 miles (12.26 km) deep. That's 0.19% of the way to the center of the Earth.
Scientists estimate it would take about 91 billion years for the core to completely solidify—but the sun will burn out in a fraction of that time (about 5 billion years).
Is the Earth's core getting hotter?
Earth's core is cooling at rates faster than previously thought, which could speed the planet's inevitable march toward uninhabitability millions or billions of years from now, researchers said this week.
Lava, when being forced from the earth, is between 700 and 1200 Celsius or roughly 1300 to 2200 Fahrenheit. The hottest fire is from an Oxyacetylene torch, also called a cutting torch, that reaches roughly 3000 Celsius or about 5400 Fahrenheit.

The dead star at the center of the Red Spider Nebula has a surface temperature of 250,000 degrees F, which is 25 times the temperature of the Sun's surface. This white dwarf may, indeed, be the hottest object in the universe.
The coldest materials in the world aren't in Antarctica or at the top of Mount Everest. They're in physics labs: clouds of gases held just fractions of a degree above absolute zero.
The distinctive blue-white color of lightning is caused by light emitted as the electrons drop back to their original energy states. Seen from above, lightning storms also produce less well-known emissions of blue or red light above the clouds, known as jets and sprites.
Lightning can boil water. The reason why many objects explode when struck is that the water they contain vaporises. So there is enough energy available.
Lightning is a discharge of electricity. A single stroke of lightning can heat the air around it to 30,000°C (54,000°F)! This extreme heating causes the air to expand explosively fast. The expansion creates a shock wave that turns into a booming sound wave, known as thunder.
The Relativistic Heavy Ion Collider has been used to throw two gold nuclei of atoms at near light speed before they collided producing a temperature 250,000 times hotter than the centre of the sun. That's 7.2 trillion degrees Fahrenheit and a new Guinness World Record.
It is commonly held that the maximum temperature at which humans can survive is 108.14-degree Fahrenheit or 42.3-degree Celsius. A higher temperature may denature proteins and cause irreparable damage to brain. Simply put, the human body can turn into a scrambled egg.
But human scientists here on Earth -- on humble Long Island, to be more specific -- have created a temperature that is much, much hotter. 250,000 times hotter, in fact. That temperature -- 7.2 trillion degrees Farenheit or 4 trillion degrees Celsius (but really, does these numbers mean anything to anyone?
How much time does the world have left?
The upshot: Earth has at least 1.5 billion years left to support life, the researchers report this month in Geophysical Research Letters.
By 2050 , the world's population will exceed at least 9 billion and by 2050 the population of India will exceed that of China. By 2050, about 75% of the world population will be living in cities. Then there will be buildings touching the sky and cities will be settled from the ground up.
There is still some uncertainty about the full volume of glaciers and ice caps on Earth, but if all of them were to melt, global sea level would rise approximately 70 meters (approximately 230 feet), flooding every coastal city on the planet. Learn more: USGS Water Science School: Glaciers and Icecaps.
At the Equator, the earth's rotational motion is at its fastest, about a thousand miles an hour. If that motion suddenly stopped, the momentum would send things flying eastward. Moving rocks and oceans would trigger earthquakes and tsunamis. The still-moving atmosphere would scour landscapes.
For all this, however, Marone says, the vast majority of the heat in Earth's interior—up to 90 percent—is fueled by the decaying of radioactive isotopes like Potassium 40, Uranium 238, 235, and Thorium 232 contained within the mantle. These isotopes radiate heat as they shed excess energy and move toward stability.