カテゴリーアーカイブ: 物理学

物理学は私の初恋だった. このカテゴリには、私の心に最も近いポストが含まれています. 今から二十年, このブログは存続している場合, このカテゴリには、おそらく私の最も永続的な洞察を開催します. そして200年後から, 私はまったく覚えていた場合, それはこれらの洞察力のためになります; ではない私は人のようなのために, 私が作るお金, でも何か. 私の最初と最後の愛のためのみ…

認知, 物理学と哲学の光の役割

現実のもの, 私たちはそれを感じるように, 非常に本物ではない. 私たちは夜空で見つ星, 例えば, 実際に存在しない. 彼らは、私たちがそれらを見ることを得る時間で移動、あるいは死亡した可能性があり. この非現実は、それが私たちに到達するために遠くの星や銀河からの光のにかかる時間に起因している. 私たちは、この遅延を知っている.

私たちはとてもよく知っていても太陽は私たちがそれを見るまでにすでに8分古いです. この事実は、特に深刻な認識論的な問題を提示していないようだ – 私たちは今、太陽で何が起こっているかを知りたい場合は、, 私たちがしなければならないすべては8分間待つことです. 私たちは、正しい 'に持っている’ 光の有限速度のために私たちの知覚の歪みを私たちが見るものを信頼することができます前に、. 見ることに同じ現象は、私たちが移動物体を感知する方法で、あまり知られていない症状があり. 彼らは何度か光の速度を移動しているかのようにいくつかの天体が表示されます, その「本当のに対し、’ 速度はそれよりもはるかに少ないでなければなりません.

何驚くべきことである (そしてめったに強調表示しない) それが来るときの動きを感知することである, 私たちは逆算することはできませんように、同じ種類の中で私達ができるように修正するために、太陽の観察の遅れのために. 私たちは本当とは思えないほど高速で移動する天体が表示された場合, 私たちはそれが本当に 'がいかに速いかさえ何の方向に計算することはできません’ 最初の特定のさらなる仮定を加えることなく移動する.

アインシュタインは歪んだとして知覚を処理することによって、問題を解決することを選んだと物理学の分野で新たな基本的な性質を発明 – 空間と時間の説明において. 特殊相対性理論の一つは核となるアイデアは、時間のイベントの順序立ての人間の概念は放棄する必要があることです. 実際には, それが私たちに到達するために離れた場所でのイベントからの光のために時間がかかるため, そして、私たちのためにそれを自覚する, 今」の概念’ もはや意味がありません, 例えば, 私たちは天文学者がそれを撮影しようとしていただけで瞬間に、太陽の表面に現れる黒点の話をするとき. 同時性は相対的で.

アインシュタインは、代わりに私たちがイベントを検出時に瞬間を利用して同時性を再定義. 検出, 彼はそれを定義されている, レーダー検出と同様の光の往復移動を伴う. 私たちは光の速度で移動する信号を送出する, と反射を待つ. 二つの事象からの反射パルスは、同じ瞬間に私たちに到達した場合, それらは同時である. しかし、それを見てのもう一つの方法は、呼び出すことが単純に二つのイベント '同時’ それらからの光は、同じ瞬間に私たちに到達した場合. 言い換えると, 私たちは、むしろそれらに信号を送信し、反射を見ているよりも、観察下のオブジェクトによって生成された光を使用することができます.

この違いは、髪分割専門性のように聞こえるかもしれない, それは私たちが作ることができるの予測に非常に大きな違いを生むん. アインシュタインの選択は、多くの望ましい特性を有している数学的な画像になり, さらなる理論展開を作ることを含む、よりエレガント. しかし、その後、, アインシュタインは信じ, 信仰の問題として、それは思われる, という宇宙を支配する規則は、「エレガントでなければなりません。’ しかしながら, それが動いているオブジェクトを記述することになると、他のアプローチは、利点があります. なぜなら, もちろん, 私たちは運動の星を見にレーダーを使用しないでください; 私たちは、単に光を感知 (または他の放射線) それらから来る. しかし、感覚パラダイムのこの種を使用して、, むしろレーダーのような検出」より,’ 醜い数学絵でユニバースの結果を記述するために. アインシュタインは承認しないだろう!

数学的な違いは、異なる哲学的スタンスを生成します, 今度は現実の私たちの物理的な画像の理解に浸透. 実例として, 私たちが観察したとし, 電波望遠鏡を通して, 空に浮かぶ二つのオブジェクト, ほぼ同じ形状の, サイズとプロパティ. 私たちは確かに知っている唯一のことは、空に、これらの異なる2点からの電波が時間的に同じ瞬間に私たちに到達することである. 波が彼らの旅を開始したとき私たちは推測することができます.

私達は仮定した場合 (私たちは日常的にそうであるように) 波は時間的に同じ瞬間に大体の旅を開始したことを, 私たちは2つの「本当の絵で終わる’ 対称ローブは、多かれ少なかれ方法は、それらを参照してください. しかし、もう一つあります, 別の可能性とそれが波が同じオブジェクトから発生したことである (その運動している) 時間内の2つの異なる瞬間で, 同じ瞬間に望遠鏡に到達する. この可能性はさらに、対称的な電波源のいくつかのスペクトルおよび時間的な特性を説明するであろう. だから私たちは本物のように、これら二つの絵のどちらを取る必要があります? 私たちはそれらを見るように、2つの対称的なオブジェクトや私たちにそのような印象を与えるような方法で1つの動画オブジェクト? それは本当に「本当の」であるかは重要ではない? ない「現実’ このコンテキストでは何の意味?

特殊相対性理論は、この質問に明確な答えを与える. 二つの物体を模倣するように数学は、このような方法で移動する単一のオブジェクトの可能性を除外. 本質的に, 私たちが見ることはそこにあるものです. まだ, 私たちが知覚するものによって、イベントを定義した場合, 理にかなっている唯一の哲学的スタンスが感知されるものの背後に横たわっている原因による感知した現実を切断するものです.

この切断は、思想の哲学学校では珍しいことではありません. 現象論, 例えば, 空間と時間は客観的な現実ではないという見解を保持している. 彼らは単に、私たちの知覚の広さ. 空間と時間で起こるすべての現象は、単に私たちの知覚のバンドルです. 言い換えると, 空間と時間知覚から生じる認知構築物である. このようにして, 私たちは、空間と時間に帰する全ての物理的特性は、驚異的な現実に適用することができます (「物事·イン·ザ·ワールドの現実’ 私たちはそれを感じるように. 根本的な現実 (その私たちの知覚の物理的な原因を保持している), 一方, 私たちの認知届かないまま.

しかし、哲学と現代物理学のビュー間の隔たりがあります. 何のためにノーベル賞受賞の物理学者をしませんでした, スティーブン·ワインバーグ, 不思議, ファイナル理論の彼の本のドリームズ, 物理学の哲学からの寄与はそう驚くほど小さいされていた理由. 物理学は、それが宇宙を見に来るという事実と折り合いをつけるためにまだ持っているので多分それはある, 目の錯覚のようなものは存在しない – 彼が言ったときゲーテは何を意味するのか、おそらくある, 「目の錯覚は、光学真実です。’

区別 (またはその欠如) 目の錯覚と真実の間に哲学の最も古い論争の一つである. 結局, それは知識と現実の区別についてです. 知識は何かについて私たちの見解であると考えられていること, 実際には, 実際には 'ケースです。’ 言い換えると, 知識は反映しています, または外部何かの精神的なイメージ, 次の図に示すように、.

ExternalToBrain

この図で, 黒い矢印は、知識を作成するプロセスを表す, その認識を含み, 認知活動, そして純粋理性の行使. これは物理学が受け入れるようになってきた写真です. 私たちの知覚は不完全であり得ることを認めつつ, 物理学は、私たちがますます微細化実験を通して外部の現実に近づく得ることができることを前提としてい, そして, さらに重要なことには, より良い理論化を通じて. 相対性理論の特殊および一般理論は、単純な物理的原理は執拗に彼らの論理的に必然的な結論を純粋理性の恐るべき機械を用いて追求している現実を、このビューの華麗なアプリケーションの例です.

しかし、もう一つあります, 長い間の周りされている知識と現実の代替ビュー. これは私たちの感覚入力の内部認知表現と知覚の現実に関してである, 下図のように.

AbsolutelToBrain

このビューでは、, 知識と知覚の現実は、内部認知構築物である, 私達は独立したと考えることになってきているものの、. 私たちはそれを知覚としては何の外部にあることは現実ではない, しかし不可知エンティティは、感覚入力の背後にある物理的な原因を生じさせる. 図では, 最初の矢印は、センシングのプロセスを表し, 第二の矢印は、認知と論理的な推論のステップを表している. 現実のこのビューを適用するためには、知識, 私たちは絶対的な現実の性質を推測する必要が, そのまま不可知. 絶対現実のための1つの可能な候補者はニュートン力学である, 私たちの知覚の現実のための合理的な予測を与える.

要約する, 私たちは知覚による歪みを処理しようとすると、, 私たちは2つのオプションがあります, または二つの可能な哲学的スタンス. 一つは、私たちの空間と時間の一環として、歪みを受け入れることです, 特殊相対性理論は、同じように. 他のオプションは、「より高いがあることを仮定することである’ 私達の感知された現実とは異なる現実, その特性が私たちが唯一の推測をすることができます. 言い換えると, 一つの選択肢は、歪みと一緒に暮らすことです, もう一つは、より高いリアリティのための教育を受けた推測を提案することであるが. これらの選択肢のいずれも、特に魅力的である. しかし、推測パスは現象論で受け入れビューに似ています. また、現実には、認知神経科学で見え方に自然につながる, その認知の背後にある生物学的メカニズムを研究する.

光と現実のこの物語のねじれは私たちが長い間、このすべてを知っているように見えるということです. 私たちの現実や宇宙を作成する際の光の役割は、西洋の宗教思考の中心にあります. 光のない宇宙は、単にあなたがライトをオフにしている世界ではありません. それは確かにそれ自体を欠い宇宙である, 存在しない宇宙. 私たちは地球が形がなかった」という声明の背後に知恵を理解する必要がこのコンテキストにある, ボイド’ 神は光があることが原因とされるまで, そこは光とする '言って。’

コー​​ランにも述べてい, 「アッラーは、天と地の光である,’ 古代ヒンズー教の著作の一つにミラー化されている: 「光に闇から私をリード, 実物に非現実から私を導く。’ 非現実的な空洞から私たちを取るの光の役割 (無) 確かに長い間理解されていた現実に, 長い時間. それは古代の聖人や預言者たちは、今だけの知識のすべての私たちの想定進歩と発見し始めている事を知っていた可能性がある?

カントの実体の、驚異的な区別は、後にphenomenalistsの間に類似点があります, とアドヴァイタにおけるブラーマン-マヤの区別. 精神性のレパートリーから現実の性質に知恵は現代神経科学に再発明されて, これは、脳が作成した認知表現として現実を扱います. 脳が感覚入力を使用しています, メモリ, 意識, 現実の私達の感覚を紡ぎ上げ中の成分として、さらには言語. 現実のこの見解, しかしながら, 何か物理学はまだとの折り合いをつけることができませんされている. しかし、ある程度のこと、そのアリーナ (空間と時間) 現実の一部である, 物理学は哲学の影響を受けていない.

実際には, 私たちは遠く私たちの知識の限界をプッシュするのと同様, 私たちは人間の努力の異なる枝の間で、これまで疑われていないと、多くの場合、意外な相互接続を発見している. まだ, すべての知識は主観的である場合にどのように知識の多様なドメインは互いに独立であることができる? 知識は、単に私たちの経験の認知表現である場合? しかし、その後、, それは知識が外部の現実の私達の内部表現であることを考えるために近代的な誤謬である, それから、したがって、明確な. 代わりに, 認識し、人間の努力の異なるドメイン間での相互接続を利用することは、私たちの集団の知恵を開発する上で、次のステージのための必須の前提条件とすることができる.

ボックス: アインシュタインの電車アインシュタインの有名な思考実験の一つは、私たちは、同時イベントによって何を意味するか再考する必要性を示している. 男はそれをすることによって高速化を見駅のプラットホームの上に立つようにそれは小さな駅を過ぎて直線軌道に沿って急いで高速列車を記述する. 彼の驚きへ, 列車は彼を通過するときに, 2ライトニングボルトは、列車のどちらかの端に次のトラックにぶつかる! (便利に, 後で研究者のための, 彼らは電車の中や地面に両方のマークを火傷しておきます。)

男へ, それは、2つの軽量化のボルトが全く同じ瞬間に打つようです. 後で, 列車のトラックによる地上のマークは、軽量化が襲ったスポットは、彼から正確に等距離にあったことを明らかにし. それ以来、ライトニングボルトが彼に向かって、同じ距離を移動, 彼らはまったく同じ瞬間に起こるの人に見えたので、, 彼はライトニングボルトが全く同じ瞬間に襲ったと結論しない理由がありません. 彼らは同時だった.

しかしながら, 少し後とします, 男はビュッフェ車の中で座っていることがたまたま女性の乗客を満たしている, 正確に列車の中央に, そして窓の外を見て時にライトニングボルトが打た. この乗客は彼女が最初に稲妻がわずかに前方に第1列車の後部に荷物車の横に倒れたときの列車の前部にエンジンの近くで地面を打つ見たことを彼に伝えます.

効果は、光が移動しなければならなかったの距離とは関係ありません, 女性と男性の両方が二点間の等距離あったように、その軽量化ヒット. しかし、彼らは非常に異なった一連のイベントを観察した.

イベントのタイミングのこの不一致は避けられない, アインシュタインは述べています, 女性は、エンジンが離れて雷のフラッシュが次の荷物の車にヒットポイントから - と近くで軽量化のフラッシュがヒットポイントに向かって移動有効であるように. 時間微量では、光線が女性に到達するのにかかる, 列車が移動するので、, 最初のフラッシュは、彼女の収縮までの距離を移動しなければならない, 第二フラッシュが移動しなければならない距離が大きくなる.

この事実は、列車や飛行機の場合には気付かれないことがあります, それは宇宙論的な距離になると, 同時性は本当に何の意味もありません. 例えば, 2遠くの超新星爆発, 地球上で私たちの視点からの同時と見られ, 他の観点から異なる時間の組み合わせで発生することが表示されます.

相対性理論で: 特殊と一般理論 (1920), アインシュタインはこのようにそれを置く:

「すべての参照体 (座標系) 独自の特定の時間を持ってい; 私たちは、時間のステートメントが参照する参照体に語っていない限り, イベントの時間の声明では意味がありません。’

Tsunami

The Asian Tsunami two and a half years ago unleashed tremendous amount energy on the coastal regions around the Indian ocean. What do you think would’ve have happened to this energy if there had been no water to carry it away from the earthquake? I mean, if the earthquake (of the same kind and magnitude) had taken place on land instead of the sea-bed as it did, presumably this energy would’ve been present. How would it have manifested? As a more violent earthquake? Or a longer one?

I picture the earthquake (in cross-section) as a cantilever spring being held down and then released. The spring then transfers the energy to the tsunami in the form of potential energy, as an increase in the water level. As the tsunami radiates out, it is only the potential energy that is transferred; the water doesn’t move laterally, only vertically. As it hits the coast, the potential energy is transferred into the kinetic energy of the waves hitting the coast (water moving laterally then).

Given the magnitude of the energy transferred from the epicenter, I am speculating what would’ve happened if there was no mechanism for the transfer. Any thoughts?

Universe – Size and Age

I posted this question that was bothering me when I read that they found a galaxy at about 13 billion light years away. My understanding of that statement is: At distance of 13 billion light years, there was a galaxy 13 billion years ago, so that we can see the light from it now. Wouldn’t that mean that the universe is at least 26 billion years old? It must have taken the galaxy about 13 billion years to reach where it appears to be, and the light from it must take another 13 billion years to reach us.

In answering my question, Martin and Swansont (who I assume are academic phycisists) point out my misconceptions and essentially ask me to learn more. All shall be answered when I’m assimilated, it would appear! 🙂

This debate is published as a prelude to my post on the Big Bang theory, coming up in a day or two.

Mowgli 03-26-2007 10:14 PM

Universe – Size and Age
I was reading a post in http://www.space.com/ stating that they found a galaxy at about 13 billion light years away. I am trying to figure out what that statement means. To me, it means that 13 billion years ago, this galaxy was where we see it now. Isn’t that what 13b LY away means? If so, wouldn’t that mean that the universe has to be at least 26 billion years old? I mean, the whole universe started from one singular point; how could this galaxy be where it was 13 billion years ago unless it had at least 13 billion years to get there? (Ignoring the inflationary phase for the moment…) I have heard people explain that the space itself is expanding. What the heck does that mean? Isn’t it just a fancier way of saying that the speed of light was smaller some time ago?
swansont 03-27-2007 09:10 AM

Quote:

Originally Posted by Mowgli
(Post 329204)
I mean, the whole universe started from one singular point; how could this galaxy be where it was 13 billion years ago unless it had at least 13 billion years to get there? (Ignoring the inflationary phase for the moment…)

Ignoring all the rest, how would this mean the universe is 26 billion years old?

Quote:

Originally Posted by Mowgli
(Post 329204)
I have heard people explain that the space itself is expanding. What the heck does that mean? Isn’t it just a fancier way of saying that the speed of light was smaller some time ago?

The speed of light is an inherent part of atomic structure, in the fine structure constant (alpha). If c was changing, then the patterns of atomic spectra would have to change. There hasn’t been any confirmed data that shows that alpha has changed (there has been the occasional paper claiming it, but you need someone to repeat the measurements), and the rest is all consistent with no change.

Martin 03-27-2007 11:25 AM

To confirm or reinforce what swansont said, there are speculation and some fringe or nonstandard cosmologies that involve c changing over time (or alpha changing over time), but the changing constants thing just gets more and more ruled out.I’ve been watching for over 5 years and the more people look and study evidence the LESS likely it seems that there is any change. They rule it out more and more accurately with their data.So it is probably best to ignore the “varying speed of light” cosmologies until one is thoroughly familiar with standard mainstream cosmology.You have misconceptions Mowgli

  • General Relativity (the 1915 theory) trumps Special Rel (1905)
  • They don’t actually contradict if you understand them correctly, because SR has only a very limited local applicability, like to the spaceship passing by:-)
  • Wherever GR and SR SEEM to contradict, believe GR. It is the more comprehensive theory.
  • GR does not have a speed limit on the rate that very great distances can increase. the only speed limit is on LOCAL stuff (you can’t catch up with and pass a photon)
  • So we can and DO observe stuff that is receding from us faster than c. (It’s far away, SR does not apply.)
  • This was explained in a Sci Am article I think last year
  • Google the author’s name Charles Lineweaver and Tamara Davis.
  • We know about plenty of stuff that is presently more than 14 billion LY away.
  • You need to learn some cosmology so you wont be confused by these things.
  • Also a “singularity” does not mean a single point. that is a popular mistake because the words SOUND the same.
  • A singularity can occur over an entire region, even an infinite region.

Also the “big bang” model doesn’t look like an explosion of matter whizzing away from some point. It shouldn’t be imagined like that. The best article explaining common mistakes people have is this Lineweaver and Davis thing in Sci Am. I think it was Jan or Feb 2005 but I could be a year off. Google it. Get it from your local library or find it online. Best advice I can give.

Mowgli 03-28-2007 01:30 AM

To swansont on why I thought 13 b LY implied an age of 26 b years:When you say that there is a galaxy at 13 b LY away, I understand it to mean that 13 billion years ago my time, the galaxy was at the point where I see it now (which is 13 b LY away from me). Knowing that everything started from the same point, it must have taken the galaxy at least 13 b years to get where it was 13 b years ago. So 13+13. I’m sure I must be wrong.To Martin: You are right, I need to learn quite a bit more about cosmology. But a couple of things you mentioned surprise me — how do we observe stuff that is receding from as FTL? I mean, wouldn’t the relativistic Doppler shift formula give imaginary 1+z? And the stuff beyond 14 b LY away – are they “outside” the universe?I will certainly look up and read the authors you mentioned. Thanks.
swansont 03-28-2007 03:13 AM

Quote:

Originally Posted by Mowgli
(Post 329393)
To swansont on why I thought 13 b LY implied an age of 26 b years:When you say that there is a galaxy at 13 b LY away, I understand it to mean that 13 billion years ago my time, the galaxy was at the point where I see it now (which is 13 b LY away from me). Knowing that everything started from the same point, it must have taken the galaxy at least 13 b years to get where it was 13 b years ago. So 13+13. I’m sure I must be wrong.

That would depend on how you do your calibration. Looking only at a Doppler shift and ignoring all the other factors, if you know that speed correlates with distance, you get a certain redshift and you would probably calibrate that to mean 13b LY if that was the actual distance. That light would be 13b years old.

But as Martin has pointed out, space is expanding; the cosmological redshift is different from the Doppler shift. Because the intervening space has expanded, AFAIK the light that gets to us from a galaxy 13b LY away is not as old, because it was closer when the light was emitted. I would think that all of this is taken into account in the measurements, so that when a distance is given to the galaxy, it’s the actual distance.

Martin 03-28-2007 08:54 AM

Quote:

Originally Posted by Mowgli
(Post 329393)
I will certainly look up and read the authors you mentioned.

This post has 5 or 6 links to that Sci Am article by Lineweaver and Davis

http://scienceforums.net/forum/showt…965#post142965

It is post #65 on the Astronomy links sticky thread

It turns out the article was in the March 2005 issue.

I think it’s comparatively easy to read—well written. So it should help.

When you’ve read the Sci Am article, ask more questions—your questions might be fun to try and answer:-)

Twin Paradox – Take 2

The Twin Paradox is usually explained away by arguing that the traveling twin feels the motion because of his acceleration/deceleration, and therefore ages slower.

But what will happen if the twins both accelerate symmetrically? That is, they start from rest from one space point with synchronized clocks, and get back to the same space point at rest by accelerating away from each other for some time and decelerating on the way back. By the symmetry of the problem, it seems that when the two clocks are together at the end of the journey, at the same point, and at rest with respect to each other, they have to agree.

Then again, during the whole journey, each clock is in motion (accelerated or not) with respect to the other one. In SR, every clock that is in motion with respect to an observer’s clock is supposed run slower. Or, the observer’s clock is always the fastest. So, for each twin, the other clock must be running slower. However, when they come back together at the end of the journey, they have to agree. This can happen only if each twin sees the other’s clock running faster at some point during the journey. What does SR say will happen in this imaginary journey?

(Note that the acceleration of each twin can be made constant. Have the twins cross each other at a high speed at a constant linear deceleration. They will cross again each other at the same speed after sometime. During the crossings, their clocks can be compared.)

Unreal Time

Farsight wrote:Time is a velocity-dependent subjective measure of event succession rather than something fundamental – the events mark the time, the time doesn’t mark the events. This means the stuff out there is space rather than space-time, and is an “aether” veiled by subjective time.

I like your definition of time. It is close to my own view that time is “unreal.” It is possible to treat space as real and space-time as something different, as you do. This calls for some careful thought. I will outline my thinking in this post and illustrate it with an example, if my friends don’t pull me out for lunch before I can finish. :)

The first question we need to ask ourselves is why space and time seem coupled? The answer is actually too simple to spot, and it is in your definition of time. Space and time mix through our concept of velocity and our brain’s ability to sense motion. There is an even deeper connection, which is that space is a cognitive representation of the photons inputs to our eyes, but we will get to it later.

Let’s assume for a second that we had a sixth sense that operated at an infinite speed. That is, if star explodes at a million light years from us, we can sense it immediately. We will see it only after a million years, but we sense it instantly. I know, it is a violation of SR, cannot happen and all that, but stay with me for a second. Now, a little bit of thinking will convince you that the space that we sense using this hypothetical sixth sense is Newtonian. Here, space and time can be completely decoupled, absolute time can be defined etc. Starting from this space, we can actually work out how we will see it using light and our eyes, knowing that the speed of light is what it is. It will turn out, clearly, that we seen events with a delay. That is a first order (or static) effect. The second order effect is the way we perceive objects in motion. It turns out that we will see a time dilation and a length contraction (for objects receding from us.)

Let me illustrate it a little further using echolocation. Assume that you are a blind bat. You sense your space using sonar pings. Can you sense a supersonic object? If it is coming towards you, by the time the reflected ping reaches you, it has gone past you. If it is going away from you, your pings can never catch up. In other words, faster than sound travel is “forbidden.” If you make one more assumption – the speed of the pings is the same for all bats regardless of their state of motion – you derive a special relativity for bats where the speed of sound is the fundamental property of space and time!

We have to dig a little deeper and appreciate that space is no more real than time. Space is a cognitive construct created out of our sensory inputs. If the sense modality (light for us, sound for bats) has a finite speed, that speed will become a fundamental property of the resultant space. And space and time will be coupled through the speed of the sense modality.

This, of course, is only my own humble interpretation of SR. I wanted to post this on a new thread, but I get the feeling that people are a little too attached to their own views in this forum to be able to listen.

Leo wrote:Minkowski spacetime is one interpretation of the Lorentz transforms, but other interpretations, the original Lorentz-Poincaré Relativity or modernized versions of it with a wave model of matter (LaFreniere or Close or many others), work in a perfectly euclidean 3D space.

So we end up with process slowdown and matter contraction, but NO time dilation or space contraction. The transforms are the same though. So why does one interpretation lead to tensor metric while the others don’t? Or do they all? I lack the theoretical background to answer the question.

Hi Leo,

If you define LT as a velocity dependent deformation of an object in motion, then you can make the transformation a function of time. There won’t be any warping and complications of metric tensors and stuff. Actually what I did in my book is something along those lines (though not quite), as you know.

The trouble arises when the transformation matrix is a function of the vector is transforming. So, if you define LT as a matrix operation in a 4-D space-time, you can no longer make it a function of time through acceleration any more than you can make it a function of position (as in a velocity field, for instance.) The space-time warping is a mathematical necessity. Because of it, you lose coordinates, and the tools that we learn in our undergraduate years are no longer powerful enough to handle the problem.

Of Rotation, LT and Acceleration

In the “Philosophical Implications” forum, there was an attempt to incorporate acceleration into Lorentz transformation using some clever calculus or numerical techniques. Such an attempt will not work because of a rather interesting geometric reason. I thought I would post the geometric interpretation of Lorentz transformation (or how to go from SR to GR) here.

Let me start with a couple of disclaimers. First of, what follows is my understanding of LT/SR/GR. I post it here with the honest belief that it is right. Although I have enough academic credentials to convince myself of my infallibility, who knows? People much smarter than me get proven wrong every day. And, if we had our way, we would prove even Einstein himself wrong right here in this forum, wouldn’t we? :D Secondly, what I write may be too elementary for some of the readers, perhaps even insultingly so. I request them to bear with it, considering that some other readers may find it illuminating. Thirdly, this post is not a commentary on the rightness or wrongness of the theories; it is merely a description of what the theories say. Or rather, my version of what they say. With those disclaimers out of the way, let’s get started…

LT is a rotation in the 4-D space-time. Since it not easy to visualize 4-D space-time rotation, let’s start with a 2-D, pure space rotation. One fundamental property of a geometry (such as 2-D Euclidean space) is its metric tensor. The metric tensor defines the inner product between two vectors in the space. In normal (Euclidean or flat) spaces, it also defines the distance between two points (or the length of a vector).

Though the metric tensor has the dreaded “tensor” word in its name, once you define a coordinate system, it is only a matrix. For Euclidean 2-D space with x and y coordinates, it is the identity matrix (two 1’s along the diagonal). Let’s call it G. The inner product between vectors A and B is A.B = Trans(A) G B, which works out to be a_1b_1+a_2b_2. Distance (or length of A) can be defined as \sqrt{A.A}.

So far in the post, the metric tensor looks fairly useless, only because it is the identity matrix for Euclidean space. SR (or LT), on the other hand, uses Minkowski space, which has a metric that can be written with [-1, 1, 1, 1] along the diagonal with all other elements zero – assuming time t is the first component of the coordinate system. Let’s consider a 2-D Minkowski space for simplicity, with time (t) and distance (x) axes. (This is a bit of over-simplification because this space cannot handle circular motion, which is popular in some threads.) In units that make c = 1, you can easily see that the invariant distance using this metric tensor is \sqrt{x^2 - t^2}.

Continued…

The Unreal Universe — Discussion with Gibran

Hi again,You raise a lot of interesting questions. Let me try to answer them one by one.

You’re saying that our observations of an object moving away from us would look identical in either an SR or Galilean context, and therefore this is not a good test for SR.

What I’m saying is slightly different. The coordinate transformation in SR is derived considering only receding objects and sensing it using radar-like round trip light travel time. It is then assumed that the transformation laws thus derived apply to all objects. Because the round trip light travel is used, the transformation works for approaching objects as well, but not for things moving in other directions. But SR assumes that the transformation is a property of space and time and asserts that it applies to all moving (inertial) frames of reference regardless of direction.

We have to go a little deeper and ask ourselves what that statement means, what it means to talk about the properties of space. We cannot think of a space independent of our perception. Physicists are typically not happy with this starting point of mine. They think of space as something that exists independent of our sensing it. And they insist that SR applies to this independently existing space. I beg to differ. I consider space as a cognitive construct based on our perceptual inputs. There is an underlying reality that is the cause of our perception of space. It may be nothing like space, but let’s assume, for the sake of argument, that the underlying reality is like Galilean space-time. How would be perceive it, given that we perceive it using light (one-way travel of light, not two-way as SR assumes)? It turns out that our perceptual space would have time dilation and length contraction and all other effect predicted by SR. So my thesis is that the underlying reality obeys Galilean space-time and our perceptual space obeys something like SR. (It is possible that if I assume that our perception uses two-way light travel, I may get SR-like transformation. I haven’t done it because it seems obvious to me that we perceive a star, for instance, by sensing the light from it rather than flashing a light at it.)

This thesis doesn’t sit well with physicists, and indeed with most people. They mistake “perceptual effects” to be something like optical illusions. My point is more like space itself is an illusion. If you look at the night sky, you know that the stars you see are not “real” in the sense that they are not there when you are looking at them. This is simply because the information carrier, namely light, has a finite speed. If the star under observation is in motion, our perception of its motion is distorted for the same reason. SR is an attempt to formalize our perception of motion. Since motion and speed are concepts that mix space and time, SR has to operate on “space-time continuum.” Since SR is based on perceptual effects, it requires an observer and describes motion as he perceives it.

But are you actually saying that not a single experiment has been done with objects moving in any other direction than farther away? And what about experiments on time dilation where astronauts go into space and return with clocks showing less elapsed time than ones that stayed on the ground? Doesn’t this support the ideas inherent in SR?

Experiments are always interpreted in the light of a theory. It is always a model based interpretation. I know that this is not a convincing argument for you, so let me give you an example. Scientists have observed superluminal motion in certain celestial objects. They measure the angular speed of the celestial object, and they have some estimate of its distance from us, so they can estimate the speed. If we didn’t have SR, there would be nothing remarkable about this observation of superluminality. Since we do have SR, one has to find an “explanation” for this. The explanation is this: when an object approaches us at a shallow angle, it can appear to come in quite a bit faster than its real speed. Thus the “real” speed is subluminal while the “apparent” speed may be superluminal. This interpretation of the observation, in my view, breaks the philosophical grounding of SR that it is a description of the motion as it appears to the observer.

Now, there are other observations of where almost symmetric ejecta are seen on opposing jets in symmetric celestial objects. The angular speeds may indicate superluminality in both the jets if the distance of the object is sufficiently large. Since the jets are assumed to be back-to-back, if one jet is approaching us (thereby giving us the illusion of superluminality), the other jet has bet receding and can never appear superluminal, unless, of course, the underlying motion is superluminal. The interpretation of this observation is that the distance of the object is limited by the “fact” that real motion cannot be superluminal. This is what I mean by experiments being open to theory or model based interpretations.

In the case of moving clocks being slower, it is never a pure SR experiment because you cannot find space without gravity. Besides, one clock has to be accelerated or decelerated and GR applies. Otherwise, the age-old twin paradox would apply.

I know there have been some experiments done to support Einstein’s theories, like the bending of light due to gravity, but are you saying that all of them can be consistently re-interpreted according to your theory? If this is so, it’s dam surprising! I mean, no offense to you – you’re obviously a very bright individual, and you know much more about this stuff than I do, but I’d have to question how something like this slipped right through physicists’ fingers for 100 years.

These are gravity related questions and fall under GR. My “theory” doesn’t try to reinterpret GR or gravity at all. I put theory in inverted quotes because, to me, it is a rather obvious observation that there is a distinction between what we see and the underlying causes of our perception. The algebra involved is fairly simple by physics standards.

Supposing you’re right in that space and time are actually Galilean, and that the effects of SR are artifacts of our perception. How then are the results of the Michelson-Morley experiments explained? I’m sorry if you did explain it in your book, but it must have flown right over my head. Or are we leaving this as a mystery, an anomaly for future theorists to figure out?

I haven’t completely explained MMX, more or less leaving it as a mystery. I think the explanation hinges on how light is reflected off a moving mirror, which I pointed out in the book. Suppose the mirror is moving away from the light source at a speed of v in our frame of reference. Light strikes it at a speed of c-v. What is the speed of the reflected light? If the laws of reflection should hold (it’s not immediately obvious that they should), then the reflected light has to have a speed of c-v as well. This may explain why MMX gives null result. I haven’t worked out the whole thing though. I will, once I quit my day job and dedicate my life to full-time thinking. :-)

My idea is not a replacement theory for all of Einstein’s theories. It’s merely a reinterpretation of one part of SR. Since the rest of Einstein’s edifice is built on this coordinate transformation part, I’m sure there will be some reinterpretation of the rest of SR and GR also based on my idea. Again, this is a project for later. My reinterpretation is not an attempt to prove Einstein’s theories wrong; I merely want to point out that they apply to reality as we perceive it.

Overall, it was worth the $5 I payed. Thanks for the good read. Don’t take my questions as an assault on your proposal – I’m honestly in the dark about these things and I absolutely crave light (he he). If you could kindly answer them in your spare time, I’d love to share more ideas with you. It’s good to find a fellow thinker to bounce cool ideas like this off of. I’ll PM you again once I’m fully done the book. Again, it was a very satisfying read.

Thanks! I’m glad that you like my ideas and my writing. I don’t mind criticism at all. Hope I have answered most of your questions. If not, or if you want to disagree with my answers, feel free to write back. Always a pleasure to chat about these things even if we don’t agree with each other.

– Best regards,
– Manoj

Anti-relativity and Superluminality

Leo wrote:I have some problems with the introductory part though, when you confront light travel effects and relativistic transforms. You correctly state that all perceptual illusions have been cleared away in the conception of Special Relativity, but you also say that these perceptual illusions remained as a subconscious basis for the cognitive model of Special Relativity. Do I understand what you mean or do I get it wrong?

The perceptual effects are known in physics; they are called Light Travel Time effects (LTT, to cook up an acronym). These effects are considered an optical illusion on the motion of the object under observation. Once you take out the LTT effects, you get the “real” motion of the object . This real motion is supposed to obey SR. This is the current interpretation of SR.

My argument is that the LTT effects are so similar to SR that we should think of SR as just a formalization of LTT. (In fact, a slightly erroneous formalization.) Many reasons for this argument:
1. We cannot disentagle the “optical illusion” because many underlying configurations give rise to the same perception. In other words, going from what we see to what is causing our perception is a one to many problem.
2. SR coordinate transformation is partially based on LTT effects.
3. LTT effects are stronger than relativistic effects.

Probably for these reasons, what SR does is to say that what we see is what it is really like. It then tries to mathematically describe what we see. (This is what I meant by a formaliztion. ) Later on, when we figured out that LTT effects didn’t quite match with SR (as in the observation of “apparent” superluminal motion), we thought we had to “take out” the LTT effects and then say that the underlying motion (or space and time) obeyed SR. What I’m suggesting in my book and articles is that we should just guess what the underlying space and time are like and work out what our perception of it will be (because going the other way is an ill-posed one-to-many problem). My first guess, naturally, was Galilean space-time. This guess results in a rather neat and simple explantions of GRBs and DRAGNs as luminal booms and their aftermath.

Discussion on the Daily Mail (UK)

On the Daily Mail forum, one participant (called “whats-in-a-name”) started talking about The Unreal Universe on July 15, 2006. It was attacked fairly viciously on the forum. I happened to see it during a Web search and decided to step in and defend it.

15 July, 2006

Posted by: whats-in-a-name on 15/07/06 at 09:28 AM

Ah, Kek, you’ve given me a further reason to be distracted from what I should be doing- and I can tell you that this is more interesting at the moment.I’ve been trying to formulate some ideas and there’s one coming- but I’ll have to give it to you in bits.I don’t want to delve into pseudoscience or take the woo-ish road that says that you can explain everything with quantum theory, but try starting here: http://theunrealuniverse.com/phys.shtml

The “Journal Article” link at the bottom touches on some of the points that we discussed elsewhere. It goes slightly off-topic, but you might also find the “Philosophy” link at the top left interesting.

Posted by: patopreto on 15/07/06 at 06:17 PM

Regarding that web site wian.One does not need to ead past this sentence –

The theories of physics are a description of reality. Reality is created out of the readings from our senses. Knowing that our senses all work using light as an intermediary, is it a surprise that the speed of light is of fundamental importance in our reality?

to realise that tis web site is complete ignorant hokum. I stopped at that point.

16 July, 2006

Posted by: whats-in-a-name on 16/07/06 at 09:04 AM

I’ve just been back to read that bit more carefully. I don’t know why the writer phrased it like that but surely what he meant was:(i) “Our perception of what is real is created out of the readings from our senses.” I think that most physicists wouldn’t argue with that would they? At the quantum level reality as we understand it doesn’t exist; you can only say that particles have more of a tendency to exist in one place or state than another.(ii) The information that we pick up from optical or radio telescopes, gamma-ray detectors and the like, shows the state of distant objects as they were in the past, owing to the transit time of the radiation. Delving deeper into space therefore enables us to look further back into the history of the universe.It’s an unusual way to express the point, I agree, but it doesn’t devalue the other information on there. In particular there are links to other papers that go into rather more detail, but I wanted to start with something that offered a more general view.

I get the impression that your study of physics is rather more advanced than mine- as I’ve said previously I’m only an amateur, though I’ve probably taken my interest a bit further than most. I’m happy to be corrected if any of my reasoning is flawed, though what I’ve said so far s quite basic stuff.

The ideas that I’m trying to express in response to Keka’s challenge are my own and again, I’m quite prepared to have you or anyone else knock them down. I’m still formulating my thoughts and I wanted to start by considering the model that physicists use of the nature of matter, going down to the grainy structure of spacetime at the Plank distance and quantum uncertainty.

I’ll have to come back to this in a day or two, but meanwhile if you or anyone else wants to offer an opposing view, please do.

Posted by: patopreto on 16/07/06 at 10:52 AM

I don’t know why the writer phrased it like that but surely what he meant was:

I think the write is quit clear! WIAN – you have re-written what he says to mean something different.

The writer is quite clear – “Once we accept that space and time are a part of the cognitive model created by the brain, and that special relativity applies to the cognitive model, we can ponder over the physical causes behind the model, the absolute reality itself.”

Blah Blah Blah!

The writer, Manoj Thulasidas, is an employee of OCBC bank in Singapore and self-described “amateur philosopher”. What is he writes appears to be nothing more than a religiously influenced solipsistic philosophy. Solipsism is interesting as a philosophical standpoint but quickly falls apart. If Manoj can start his arguments from such shaky grounds without explanation, then I really have no other course to take than to accept his descriptions of himself as “amateur”.

Maybe back to MEQUACK!