NASA has just deliberately crashed a spacecraft into an asteroid to see if it can alter its orbit.
The asteroid is called Dimorphos, and it orbits another asteroid called Didymos.
It was fascinating to watch. NASA’s live feed began at about 10.15 BST, at which point the Didymos/Dimorphos pair was visible as just a small dot a few pixels wide from the onboard camera. At that stage, impact was about an hour and half away. It was basically a live video with a frame rate of a few seconds, and at the start nothing much was happening.
As time ticked by, the dot became larger, and then it became possible so discern Dimorphos to the upper right of the frame (top image).
Closer – Dimporphos heading past Didymos
As impact time approached, things changed rather more quickly. Detail on Didymos became visible, and Dimorphos came clearly into view. Then, Didymos passed out of frame as the spacecraft autonomously targeted Dimorphos.
Dimorphos with detail
Impact then occurred with a final view of the surface of Dimorphos.
DART was accompanied by LiciaCube, which monitored the collision from about 50km away, and pictures from that should appear shortly (over the next few days) – which will also be interesting. However, it will be a while before they know if the orbital period has changed, indicating a successful outcome of the overall experiment.
But whatever. It is success enough to have targeted something about 160m wide and nearly 7 million miles away so accurately using autonomous control within the probe like this. Another NASA success, no matter how you look at it.
Yessss! The weather finally cleared up and I finally saw Comet Neowise with my own eyes.
This is just a handheld short-exposure shot, but it’s clearly there. And you can see it with the naked eye even in well-lit areas. It has a long visible tail.
If the weather looks good tomorrow, I might drive somewhere darker to try it with my tripod. And a longer exposure – trust me, with the naked eye, the tail is much more pronounced, but a snapshot doesn’t pick it up properly.
But the main thing is, I saw a comet! And a proper one with a tail.
The Mirror has some handy advice for people who might want to watch the Lyrid meteor shower this weekend.
Apparently, you need to look up at the sky to see if it’s clear, because if it’s not you won’t see anything. Having established the clarity of the sky, you then need to keep looking up because that’s where the meteors will be.
I’m glad they told me that. I’d never have figured it out by myself.
Somewhat more relevant, other than the fact that it is the “second brightest star in the sky”, is that Vega is in the North East (the two stars on the handle side of the pan of The Plough point roughly towards it). The Mirror doesn’t mention that – which is odd, since most of its readers would probably need help finding the sky, let alone a specific star given only by name.
Just regarding that last post about Rosetta, and one of the images I have shown again here:
If you get the full sized image here, in the black sky to the middle left there is a small white dot that might be a star, a data glitch, or just an aberration on the optics. But look what happens when you blow it up:
It’s a disk shape with several lobes around it. Here’s what happens when you adjust the contrast:
Is that strange or what? I’d have never spotted it if I hadn’t seen the comments under that photo.
No one else seems to have picked up on a possible UFO in this latest Rosetta image.
There’s bound to be a logical explanation. On the list of possible logical explanations, it being a real out-of-this-world UFO comes in somewhere at around the gazillionth position.
Mind you, it doesn’t half look like that photo in Independence Day when they first detect the aliens approaching.
Actually, it is definitely some sort of exposure artefact. Every time a star appears in any Rosetta image you see some sort of streaking and those lobe-like structures. In another image from the final descent you can see multiple stars and they all show the same features.
The Rosetta probe went into orbit around Comet 67P/Churyumov-Gerasimenko in August 2014, after a 10-year journey which saw it travel more than 4 billion miles as it swung around Mars and Earth (three times) to pick up speed. Finally, a critical deceleration phase as it neared 67P slowed it from almost 800 metres per second to a more sedate 8 metres per second, after which orbit was established.
This in itself was an incredible feat, but there was more to come. In November 2014 Rosetta discharged a small lander, known as Philae, which landed on the comet’s surface. I suppose success is a relative term, since Philae’s system for attaching itself to the comet was – with hindsight – possibly a little too much the stuff of science fiction. The theory was based on the assumption that comets are merely big balls of ice with dirt mixed in, and Philae was equipped with explosive harpoons which were supposed to be fired into the surface on contact and hold it there while it used threaded feet to screw itself down. I don’t think anyone is 100% certain, but it was believed that the harpoons didn’t fire, and consequently Philae bounced back into space and landed again – this time in a location which was believed to be dark and shielded so that an erratic signal was received and the solar panels were unable to keep it powered up. Nevertheless, it did send back some photographic data before going silent for more than a year.
It was believed that if Philae were to suddenly be exposed to sunlight again it would wake up, and that this might happen as the comet went around the Sun and the rotational axes shifted. This didn’t happen as planned, though a very brief signal indicating full functionality was detected before the Rosetta-Philae link was shutdown to conserve power in mid-2015. It wasn’t quite the end, because only a month or so ago Rosetta incredibly produced a picture (composite, above) which clearly showed Philae pretty much upside down and wedged under a rocky cliff.
In the end, Philae didn’t actually achieve much – if you don’t count actually touching down very nearly safely on something travelling at 34,000 miles an hour around 300 million miles away as an achievement in itself! It nearly worked – nearly, but not quite. It didn’t drill and analyse samples as was originally intended. And personally, I wouldn’t rule out the possibility that comets are not the big snowballs they’ve always been reckoned to be and are somewhat harder – such that when Philae’s harpoons fired, instead of penetrating as the theory said they should, they bounced off and the thrust pushed Philae back into space before the weak gravity pulled it back down and dumped it in a crevice (I’m just surmising, OK?) I mean, does this look like a “dirty snowball”?
As Comet 67P passed around the Sun in 2015 and began to move away into space it was always known that it would eventually be too far away for Rosetta to remain powered and operational. They could have hibernated it until 67P came back again in about 7 years’ time, but the chances of Rosetta successfully coming out of hibernation were slim (it was not designed to withstand such conditions and the risk was great). The decision was made to land Rosetta on 67P instead – more or less a low-speed crash landing.
Well, that happened today, and the image above was captured just 20 metres above 67P (that’s just slightly less than the distance you need to be able to read a car number plate from for your driving test). Apparently, the comet is so far away now that the data transfer rate is only about the same as it was on the Internet when we used to rely on dial-up modems. The width of the surface shown in the image is about 2.5m – two or three adult paces.
I’m still making the most of the clear weather, which is forecast to come to an end this weekend. The moon is almost at its third quarter and the angle of the sun is showing just how uneven the earth-facing side really is.
I bought a new tripod, and this one is much more solid and easy to adjust than the super-cheap one I was using.
I should point out that I’m only doing this because I was surprised at how much detail I could get when I when I did that test photo last week (before the eclipse). So I thought I’d experiment.
The picture below shows the same area of the moon (two craters, in particular) as they appeared at full moon last Sunday and subsequently up until tonight.
At full moon, the two craters I have outlined are barely discernible as the sun’s light falls directly on to them. As the sun’s position changes, the craters become progressively more visible as shadows are cast by their walls. The edge of what I think is the Mare Imbrium is also more sharply defined, and craters which weren’t even visible to begin with suddenly appear.
Having seen the effect of the sun casting shadows across the face of the moon I took the opportunity to catch the latest phase tonight. The moon rises later each night, and it is quite low on the horizon – which led to this lucky shot.
Anyway, after moving away from the Silver Birch tree, this is the detail visible tonight.
I was brought up to believe that although there were craters on the moon, much of it – and certainly the front – was like a big dusty desert. Apollo mission photos did a lot to create this impression.
When I was a child I used to have a telescope, but it wasn’t very powerful – as I’ve discovered the last week or so, much less powerful than the telephoto lens on my camera. With my telescope, you could just make out mountain ranges at the edge of the sun’s coverage, but little else. How times change.
The areas on the moon you think of as being quite featureless show up as being pocked by craters.
Even the edges of the “seas” (or maria) are seen to cast shadows, suggestive of steep sides.
It’s a clear night and I couldn’t resist getting a few more snaps of the moon now that it is waning. It’s amazing how much extra detail you get when the sun starts casting shadows instead of just hitting square on, as it does when the moon is full.
This one shows the top corner.
This is the top middle corner.
Here’s the lower middle.
And finally, the bottom.
At this rate, I’ll need to grow a beard and buy some horn-rimmed glasses.
I stayed up late last night to watch the eclipse. Here are some of the photos I took. First of all, the moon at around 10.30pm Sunday (before anything had started):
Now, the moon at about 1.20-am Monday morning. There was a hint of something in the top left, though it isn’t easily seen in the photo:
This next one is at around 1.40am. Definitely something happening now but still not easily discernible on the photo:
Now, the appearance at about 2.10am Monday. Absolutely no mistaking it now:
This one is from around 2.30am:
This is at 2.55am. I’d left it a bit long and it had progressed further than I expected:
I noticed that although the reddish tinge was visible to the naked eye, I was focusing on the lit part of the moon so was getting quite a fast exposure – meaning that the red part wasn’t showing up. This next image is from the same time (2.55am), but with my focus on the darker part. The lit part is over-exposed slightly as a result:
By now, it had almost reached totality and over-exposure wasn’t as much of a problem. This is from around 3.15am.
Here’s another from the same time, with the focus shifted slightly:
And finally around 3.40am. I couldn’t stay up any longer as I had to go to work in the morning (note that exposure time was so long you can even see a couple of stars just to the right):
And another different exposure from the same time:
If I ever do anything like this again, I’ll check to make sure forecast times are in BST and not GMT – everything was an hour later than I’d expected!
Anyone who is interested in this sort of thing will already know that Sunday night/Monday morning there will be a total lunar eclipse which coincides with a “supermoon” (where the moon is as close to the Earth as it gets, therefore at its largest). It’s quite a rare event, and another one isn’t due until 2033. The UK is also being dominated by high pressure at the moment, which promises clear skies.
I’m planning to take some pictures of it, and if we DO get a clear sky then they should look like the one above. I took this tonight using a tripod and remote control shutter release with my Panasonic Lumix FZ200. You get an idea of how good this camera is for the price when you zoom in on the image a little.
If all goes to plan, I should be able to get a good set of images covering the eclipse.
Yessss! The weather finally cleared up and I finally saw Comet Neowise with my own eyes.
The Mirror has some handy advice for people who might want to watch the Lyrid meteor shower this weekend.
