あの奇妙な星がさらに奇妙に ― そしてエイリアンの可能性も
That bizarre-looking star just got a lot weirder — and yes, it could be aliens
費用・技術から読みとく巨大建造物の世界史 (じっぴコンパクト新書)
posted with amazlet at 16.01.24
Three months ago, news broke that a giant "alien megastructure" could exist around a bizarre-looking star 1,500 light-years away.
3ヶ月前、1500光年彼方の奇妙な見た目の星の周囲に、「エイリアンの巨大建造物」が存在する可能性があるというニュースが出ました。
- bizarre - 奇妙な
- weirder - 奇妙
While the prospect of aliens was first launched by Penn State astronomer Jason Wright, almost everyone in the astronomy community agreed that the chances that this was the case were "very low."
このエイリアンの見通しはペンシルバニア州立大学のJason Wrightによって初めて出されたものであり、 天文学コミュニティのほぼ全員が、その可能性は「とても低い」としていました。
Now, the latest investigations into this strange star by Louisiana State University astronomer Bradley Schaefer have reignited the alien theory, New Scientist reported.
しかし今、ルイジアナ州立大学の天文学者Bradley Schaeferによる、この妙な星についての最新調査で、エイリアン説を再浮上させました。 New Scientistが報告します。
- reignited - 再燃
What makes this star, KIC8462852, so bizarre is the drastic changes in light we see from it over time. Many stars experience temporary fluctuations in brightness, increasing and decreasing in luminosity over time, but KIC8462852's changes are severe by comparison.
Between 2009 and 2013, astronomers using the Kepler space telescope discovered that it would sometimes lose up to 20% of its brightness. What's more, the changes didn't follow any obvious pattern.
That would suggest something gigantic must be blocking the light at random times, meaning that it couldn't be a planet or other regular orbiting object because that would generate a distinct pattern of dimming light. It must be something that changes shape over time, thereby blocking different levels of light at random intervals.
輝度が最大20パーセントも落ちることがあり、その明滅パターンにまったく規則性がないため、 巨大な構造物が光をランダムに遮っていると示唆されうる。 それは惑星や他の通常の軌道上の物体ではありえない、独特の光の落ち方を作り出しているのです。
Surprise: It's probably not comets
サプライズ：おそらく彗星群ではない
An alien megastructure, called a Dyson swarm, was suggested as one explanation for what scientists have observed, but the most likely reason astronomers came up with was comets — a giant family of them.
But Shaefer says not so fast.
天文学者は彗星の大群による説明が妥当だとしました。しかし、Shaeferはそんなに速くはないと言います。
"The comet-family idea was reasonably put forth as the best of the proposals, even while acknowledging that they all were a poor lot," Schaefer told New Scientist. "But now we have a refutation of the idea, and indeed, of all published ideas."
「彗星の大群と考えるのは、それらが酷くたくさんあったということを認めさえすれば、最高の提案として薦められる合理的なものでした。 しかし、いま、私たちは、反論、そう、公開されている全てに反する考えを持っています。」
- acknowledging - 認める
- refutation - 反論
To make his discovery, Schaefer had to dig deep down into the astronomy archives at Harvard. It turns out, astronomers have data on KIC8462852 dating back as far as 1890.
By analyzing over 1,200 measurements of this star's brightness taken from 1890 through 1989, Schaefer found that the irregular dimming of KIC8462852 has been going on for over 100 years. Schaefer published his findings in the online preprint server arXiv.org.
What's more, he explains in his paper that this "century-long dimming trend requires an estimated 648,000 giant comets (each with 200 km diameter) all orchestrated to pass in front of the star within the last century," which he said is "completely implausible."
百年の長さの光の明滅には、648000個の巨大彗星（直径200キロメートル）が、百年以内に、いっせいに星の正面を横切らないといけない。 これは、完全に信じがたい。
So what is it?
では、それはなんでしょうか？
By killing the comet theory, Schaefer has brought us one step closer to finding out what is really happening around KIC8462852.
At the same time, he's also reignited the possibility that the source could be an alien megastructure that an advanced alien civilization has been slowly building over time. One thing's certain for Schaefer: The bizarre dimmings are probably caused by a single, physical mechanism that's undergoing some type of ongoing change.
"The century-long dimming and the day-long dips are both just extreme ends of a spectrum of timescales for unique dimming events, so by Ockham's Razor, all this is produced by one physical mechanism," Shaefer said in his paper. "This one mechanism does not appear as any isolated catastrophic event in the last century, but rather must be some ongoing process with continuous effects."
Schaefer isn't the only one interested in learning more about KIC8462852. Late last year, astronomer Doug Vakoch and his team at the new organization called SETI (Search for Extraterrestrial Intelligence) International — not to be confused with the SETI Institute — went hunting for aliens around KIC8462852.
They searched for signals that an alien civilization might be beaming toward Earth either in radio or visible wavelengths, but ultimately they came up empty handed. So, if it is aliens, then they're being awfully quiet.
