Dela Cruz, if you haven’t seen all of his art you should.
Cosmic clouds seem to form fantastic shapes in the central regions of emission nebula IC 1805. Of course, the clouds are sculpted by stellar winds and radiation from massive hot stars in the nebula’s newborn star cluster, Melotte 15. More popularly known as The Heart Nebula.
Image: David Kingham
The Perseids are a prolific meteor shower associated with the comet Swift-Tuttle. The Perseids are so-called because the point from which they appear to come, called the radiant, lies in the constellation Perseus. The name derives in part from the word Perseides (Περσείδες), a term found in Greek mythology referring to the sons of Perseus.
The stream of debris is called the Perseid cloud and stretches along the orbit of the comet Swift-Tuttle. The cloud consists of particles ejected by the comet as it travels on its 130-year orbit. Most of the dust in the cloud today is around a thousand years old. However, there is also a relatively young filament of dust in the stream that was pulled off the comet in 1862. The rate of meteors originating from this filament is much higher than for the older part of the stream. —[**]
Kees Veenenbos: Mars
Dutch artist Kees Veenenbos is one of the leading digital artist who creates amazing renderings of space and planetary landscapes. His work has been featured in National geographic on numerous occasions, as well as being used in several NASA’s projects. In fact, majority of his Mars digital elevation models have been used by NASA depicing beautiful images of Mars, including creative concept renderings with water and ice present on the Martian surface.
[via Empty Kingdom]
The world is a flat disc balanced on the backs of four elephants which, in turn, stand on the back of a giant turtle called Great A’Tuin.
Ten Things You May Not Know About the Sun
1) You won’t go blind looking at it. Probably.
No one has ever been permanently and totally blinded by looking at the Sun. You can hurt your eyes, but the damage is usually not total, and a lot of it heals (though not always completely)
2) The Sun is not an average star.
As with most things in nature, the number of objects depends on the size. There are very few high mass stars, more intermediate mass stars, and gazillions of low mass stars. Roughly 10% of all stars by number in the Milky Way Galaxy are like the Sun, which means that very few are more massive. Even being conservative, I’d say that the Sun is more massive than 80% of the stars in the Galaxy. That’s hardly average!
3) The Sun converts matter into energy.
It’s because of that whole E = mc2 thing. Seriously. The Sun is pretty big; at 1.4 million kilometers across it has a million times the volume of the Earth! That means that at its core, at the very center of the Sun, the pressure and temperature are ridiculously high (340 billion atmospheres and 16 million degrees Celsius (27 million degrees Fahrenheit)); so high that hydrogen can undergo nuclear fusion and turn into helium.
4) It would be invisible to the naked eye 60 light years away.
Of course, the farther away an object, the fainter it gets. It turns out that the Sun fades to 6th mag at a distance of roughly 60 light years. Now, that’s a long way by human standards — 600 trillion kilometers, or 360 trillion miles — but on the galactic scale that’s still breathing down our necks; the Milky Way is 100,000 light years or one quintillion kilometers across. That’s 1,000,000,000,000,000,000 kilometers. A lot. In the illustration above of the Milky Way, 60 lights years is less than half a pixel. The galaxy is huge.
5) The Sun is not yellow.
This one causes a lot of confusion. Let me be clear: the Sun emits light at all different colors; red through violet. The amount it puts out at different colors is different, though. In fact, it emits most strongly in the blue-green part of the spectrum (around 480 nanometers)… but it doesn’t look green because our eye (with help from the brain) combines all those different colors.
Technically, the Sun is white. This is easy to show: a piece of paper held up to sunlight appears white, as do snow and clouds. If the Sun were yellow, those would look yellow.
6) It solved a major problem in physics… and then created another one.
The idea that stars use nuclear fusion to generate energy is credited to Hans Bethe, who thought of it in the 1930s. In the 1950s, an incredible paper came out describing the detailed nuclear reactions going on in the cores of stars.
The physics involved made a prediction: the Sun should be emitting neutrinos, energetic subatomic particles that are a severe pain in the neck to detect. The first solar neutrinos were detected in the 1960s, which was very cool. But there was a problem: only 1/3 of the predicted neutrinos were found.
7) The Sun can blow out satellites and even cause blackouts on Earth.
At any time, the magnetic field of the Sun is fiendishly complex, but near the peak of the magnetic cycle it gets very strong, too. It can get tangled up near the surface, like a sack full of bed springs, and store a huge amount of energy. If something happens — a line gets crossed, for example — that energy can be released. It can cause a solar flare, a massive explosion of matter and energy from the Sun’s surface, or a coronal mass ejection (or CME), a vastly larger eruption of material. A CME can slam us with high-energy subatomic particles, and a good flare can send high-energy gamma rays our way as well, a double-whammy of nastiness.
Either of these can fry a satellite. They generate massive amounts of currents in the materials making up satellites, which can arc and blow out circuits. Most satellites can withstand a minor onslaught, but quite a few have been lost in bigger events.
We can be affected down here on Earth’s surface, too. The Earth’s magnetic field gets rung like a bell when slammed by a CME, which can generate vast currents under the Earth’s surface. These geomagnetically induced currents, or GICs, can dump a lot of extra current into the power grid, causing widespread blackouts.
8) The peak of solar activity is not at the same time as the magnetic field peak.
The Sun’s field actually peaks twice; there is a first peak which then declines over about a year, then a slight resurgence for about a year, then a decline which leads down to the minimum — it looks like a double-humped camel’s back (technically, a Bactrian camel, if a zoologist happens to be reading this). The peak of flare and CME activity is actually associated with that second peak, with more and more violent solar explosions occurring then. This last occurred in November 2003, when the Sun went nuts, blasting out flare after flare in a series that stunned astronomers (I attended a special meeting for solar astronomers about this event, and they were all aghast at what the Sun had done). The image above (in false color) shows one flare that happened on November 4, 2003, and you can see it was quite a bruiser.
9) It’s getting hotter.
The Sun is fusing hydrogen into helium in its core. It doesn’t have enough mass to squeeze the helium enough to fuse it (it takes far higher pressure and temperature to fuse helium into carbon), so that helium builds up in the core, like ash in a fireplace. As more of it piles up, its own gravity squeezes it. When you compress a gas it heats up, and that helium is basically just a gas, though a very hot and high-density one. So for billions of years, as the very center of the Sun has had more and more helium pile up, it’s been getting hotter.
That extra heat works its way out from the center and eventually out through the surface. So, over time, the Sun itself, even its surface, is getting hotter. A hotter star is brighter… which means the Sun is getting brighter, too. In fact, it’s about 40% brighter now than it was when nuclear fusion first switched on 4.5 billion years ago. And it’s still getting hotter now.
10) The Sun has 6.3 billion more years to live.
Right now, the Sun is 4.55 or so billion years old. It’s been getting hotter all that time, but in general, from day to day, it’s been a stable star shining steadily.
In 6.3 billions years, that’ll all change.