The Earth and Moon from between the rings of Saturn

Tuesday, 25 April, 2017

Earth from Saturn, by Cassini, via NASA

Here’s a view you don’t see every day, Earth, and the Moon – the very faint dot to the left of Earth – as seen from between gaps in the rings of outer planet, Saturn.

This will be one the last batch of images from the Cassini space probe, before it is set on a collision course with the ringed planet. See a larger version of the photo here.

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Who is up for a final spin on Cassini before it crashes into Saturn?

Friday, 7 April, 2017

In September the Cassini space probe, which has spent thirteen years studying Saturn, with its fuel supplies nearly exhausted, will set itself on a collision course with the ringed planet.

Before diving into Saturn’s atmosphere, and disintegrating in the process, Cassini is scheduled to make twenty-two plunges into the region between the planet and its rings, an area that has been little explored to date.

I wouldn’t mind being on board for one or two of those passes, though obviously not the final one. Much as I like Saturn, I have no desire to become part of it.

And in honour of its work, a selection of Cassini’s best Saturn photos, compiled by Gizmodo.

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The true size of the solar system, seen with an animation

Tuesday, 28 March, 2017

A proposal to reclassify what a planet is, may see the planet count of our solar system jump from eight, to one-hundred-and-two bodies. The latter number would certainly make the Sun’s family sound large. But what is the size of the solar system in terms of the amount of room it occupies in interstellar space?

From a human’s perspective, the answer again would be big. Enormous, most likely. An animation, by Imgur member Disclaimered, depicts the solar system as the crew of a departing starship might see it on their way out of it. It offers some sense of scale. The clustering of white lines, visible at about the ten second mark, are dwarf planets.

According to one estimate, there may be ten thousand such bodies, situated beyond the orbit of Neptune, in orbit around the Sun. Ten thousand dwarf planets. That’s a staggering number. The solar system is big, no matter what way you look at it.

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Make Pluto great again, but not every other dwarf planet there is

Thursday, 23 March, 2017

Nearly eleven years after losing its status as a fully-fledged planet of the solar system, dwarf planet Pluto stands to be reinstated to the big league. But it won’t be alone. Another one hundred bodies, orbiting the Sun, many of them likewise dwarf planets, stand to be upgraded.

Were this to happen, the size of the solar system, in terms of the number of planets it has, would swell. Instead of the current eight planets, there would be one hundred and two. I don’t know about you, but that seems excessive.

When Pluto was relegated to dwarf planet status, I, like many others, wasn’t happy about it. But now it seems quite reasonable. Pluto, for instance, is only seventy percent the size of the Moon, and just under twenty percent the size of Earth. Referring to it as a planet seems absurd.

On the other hand, dwarf planet isn’t much of a designation either. Perhaps we need to rethink the way bodies of the solar system are classified all together? My suggestion, keep the eight planets of the solar system as they are, and consider anything smaller than Mercury, a “member”.

On reflection though, that will probably only create yet more problems, and disagreement. Instead, let’s reinstate Pluto as a planet, a honourary planet, since for a long time it was always regarded as such. Then reserve labels like dwarf planet to bodies discovered after Pluto.

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Planets, moons, and stars, made to order by the Little Planet Factory

Wednesday, 8 March, 2017

Jupiter, Earth, Saturn models by Little Planet Factory

Astronomy geeks will love this, 3D printed models of the planets, and moons, of the solar system, made by George Ioannidis of the Little Planet Factory. Above is an image of Earth posing with Jupiter, and a sans-rings Saturn.

You can also order the Sun. And the three stars of the Alpha Centauri, and Proxima Centauri system, our nearest neighbours in interstellar space. Or the Moon. Or Mars, when it once had oceans. And much more.

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Saturn’s rings, as seen in unprecedented detail, by Cassini–Huygens

Friday, 3 February, 2017

Saturn's rings, photo via NASA

NASA’s Cassini–Huygens automated space probe has been orbiting Saturn, the sixth planet of the solar system, since 2004. During that time it has taken countless photos, including this set, that show’s the planet’s ring system in intricate detail. Incredible. Here’s a larger version of the above photo.

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The sun’s pretty big right, how hard then can it be to crash into it?

Thursday, 28 July, 2016

I’m no physicist, but I would have thought that the Sun would be the easiest object in the solar system to crash into. But what’s up with crashing stuff into the Sun, in the first place?

Well, people are interested in doing so, as they think it might help us get rid of nuclear waste that is stockpiling on Earth. If it were to be incinerated by the Sun, it would no longer be a problem, right?

Hitting the Sun, however, is far from simple, and if it were to be tried, would be easier to arrange from the outer reaches of the solar system, say where Pluto is, than from near Earth. Who’d have thought? I guess that’s exactly why I am not a physicist.

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Super, there may be a super-earth somewhat near Earth

Wednesday, 13 January, 2016

Astronomers may have found a super-earth planet, a body that is like our home planet, but a little larger, lurking in the far reaches of our very solar system, some three hundred astronomical units, or AU, from the Sun. An AU is the mean distance between the Earth and the Sun.

For reference Pluto is an average of about forty AU from the Sun, so this object, if it is a super-earth, and it is indeed a member of our solar system, is a long way from home. Perhaps, if it is an Earth like planet, and there is still some doubt on that point, we could move there one day… if we can find a way to sufficiently heat the place, that is.

Another possibility (which seems more likely to the object’s discoverers) is that it is about 300 AU away and about 1.5 times the size of Earth, making it the first “super-Earth” found in our solar system. Observations of trans-Neptunian objects have led to some speculation that one or two super-Earth’s could lurk in the outer solar system, so it’s not out of the question.

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Sights we’ve seen in the solar system between here and Pluto

Friday, 3 July, 2015

It’s just a little over a week until NASA’s New Horizons space probe makes its closet approach to dwarf planet Pluto. The fun begins in earnest in the weeks following the flyby, when the data collected by the probe reaches Earth.

While we wait for that to happen, here’s a collection of images taken by other probes, of some of the planets and moons in the solar system, in the past.

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Putting out the Sun with water is like putting it out with gasoline

Monday, 12 January, 2015

If you had a bucket as large as the Sun, full of water, could you extinguish the Sun with it? No. It will probably flare up and fry you.

It is a really good question. Maybe too hard to answer for anybody but an astronomer with some very special software, as nothing like this happens in nature. In nature, a star makes a lot of carbon before it makes any oxygen, and here the oxygen is supplied first. But the probable answer is “no.” The Sun involves a special type of fire that is able to “burn” water, and so it will just get hotter, and six times brighter.

So what then to do with a body of water that cannot in fact dowse the Sun? Float Saturn in it instead? Ever heard the one about the ringed planet being able to float in water, were there a vessel big enough to hold it? Yet that doesn’t appear to hold much water either.

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