Kepler, the planet-hunting space telescope, is dead

3,000 potential exoplanets later, a failed reaction wheel means the end of the Kepler mission.

The Kepler telescope, a one tonne satellite launched in 2009 to scan for planets outside of our solar system, is dead.

Over the four years of its mission, the spacecraft has found over 3,000 stars which might have planets orbiting them, and the earth-based analysis has confirmed 134 planets orbiting 76 of them.

In April, the mission even announced the discovery of two potentially habitable planets. The two were roughly earth sized, and roughly earth temperature as well. Each of them might just lie in the "habitable zone", where liquid water can potentially exist.

Sadly, shortly after that discovery, Kepler ran into problems. The telescope manoeuvres through space with four reaction wheels, which keep it pointing in the right direction using a gyroscope effect. In July 2012, one of the wheels failed, but the mission was designed to only require three to accurately aim. In May this year, however, a second wheel failed. Yesterday, Nasa announced that they had given up trying to fix the wheels. Kepler can no longer be targeted accurately.

But, good news! Rumours of Kepler's death have been greatly exaggerated (by me, in paragraph one. Sorry.), because while the telescope can't be aimed any more, it's still useful. The imaging functionality works fine, and with two remaining reaction wheels and a limited amount of thruster fuel left it's even got a bit of manoeuvrability. NASA has opened it up to the community to work out the best way to make use of what's left working; one proposal, for instance, involves heavily post-processing the images to remove drift caused by the lack of a third wheel.

There's hope for the mission yet, which is great, because as Ars Technica's John Timmer writes, there's a lot more to learn:

A longer mission would identify planets further from their host stars. To identify a candidate, Kepler needs to see it pass between Earth and the star the exoplanet orbits three times. The further out a planet is, the longer one orbit takes, so the longer it will need to do three passes. As such, the existing data is heavily biased toward planets that orbit very close to their host stars; this also means that most of the potentially habitable planets we've spotted are orbiting dwarf stars, which are dim enough that water can remain liquid close in.

In other words, we simply haven't looked long enough to detect planets in a habitable zone around energetic stars. We have a much better picture of the diversity of exoplanets, but it's far from a complete one.

Kepler. Photograph: Wikimedia Commons

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

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"Death to all Jews": Why Disney dropped YouTube's biggest star PewDiePie

The Minecraft vlogger turned internet celebrity's taste for shock comedy was too much for the family-focused corporation. 

Disney has cut ties with YouTube’s most-subscribed star after he paid two Sri Lankan men five dollars to hold up a sign that read “DEATH TO ALL JEWS”.

Feel free to read that sentence again, it’s not going anywhere.

A still from PewDiePie's video, via YouTube

PewDiePie, real name Felix Kjellberg, has over 53 million subscribers on YouTube, where his videos about gaming earned him over $15m last year. The 27-year-old, whose content is popular with children, came under fire this month after the Wall Street Journal investigated anti-Semitic comments in his videos. In one video, a man dressed as Jesus says “Hitler did absolutely nothing wrong”, while in another Kjellberg used freelance marketplace Fiverr to pay two men to hold up the offensive sign. The videos have since been deleted.

Jumpcut.

The Walt Disney Company became affiliated with PewDiePie after they bought Maker Studios, a network of YouTube stars, for nearly $1bn in 2014. Following the WSJ’s investigation, Maker dropped the star, stating: “Although Felix has created a following by being provocative and irreverent, he clearly went too far in this case and the resulting videos are inappropriate. Maker Studios has made the decision to end our affiliation with him going forward.”

When you sack a YouTube Star, makes no difference who they are.

Via Wall Street Journal

But why should the story stop there? Neo-nazi website The Daily Stormer are now defending PewDiePie, while the notoriously politically-incorrect 4Chan forum /pol/ have called him “our guy”.  

In his defence, Kjellberg wrote a blog post denying an affiliation with anti-Semitic groups and explained his actions, writing: “I was trying to show how crazy the modern world is, specifically some of the services available online.” In a video last December the star also said: "It's extremely annoying how I can't make jokes on my channel without anyone quoting it as actual facts, like something I actually said", before dressing as a soldier and listening to one of Hitler's speeches while smiling. 

Pause.

(If all of this sounds familiar, recall when disgraced YouTuber Sam Pepper claimed a video in which he groped unsuspecting females was a “social experiment”).

Play.

And yet the story still isn’t over. Disney have learned a hard lesson about assuming that YouTubers are the squeaky clean fairy-tale princes and princesses they often appear to be. Shay Butler, one of the original founders of Maker Studios, yesterday quit the internet after it was alleged he sent sexual messages to a cam girl via Twitter.

Butler is one of the original "family vloggers", and has spent nine years uploading daily videos of his five children to YouTube. A practicing Mormon, Butler has become emblematic of family values on the site. “My heart is sick,” he wrote on Twitter, neither confirming nor denying the allegations of his infidelity, “I have struggled with alcoholism for years… My purpose is to rehab.” 

The result is a very dark day for YouTube, which has now dropped Kjellberg from its premier advertising network, Google Preferred, and cancelled the second series of the star's reality show, Scare PewDiePie

Amelia Tait is a technology and digital culture writer at the New Statesman.