Freethought & Rationalism Archive

The Lost Number · 08-09-2002, 08:05 PM

That is to say, matter which is (probably among other things) repellant to gravity. If dropped, it would "float up".

Could this stuff exist anywhere in the universe?
Can it be created, and if so, how?
What would be the potential danger/s of it?

tronvillain · 08-09-2002, 09:22 PM

As far as I know, "negative matter" is not currently even a theoretical possibility, so to answer your questions:

1) No. Well, it is not a theoretical possibility, but it is a logical possibility, so I can't quite rule it out entirely. It's near enough that I can ignore the possibility though.

2) No. As I said it is not a theoretical possibility, so creating it pretty much out of the question.

3) None. Well, other than experiencing gravity negatively you have assigned it no properties so it is impossible to speculate on what dangers it might present if it did exist, which it doesn't.

NialScorva · 08-09-2002, 10:10 PM

There are actually quite a few equations that can allow for negative mass, but no evidence as of yet for it.

<a href="http://www.physlink.com/Education/AskExperts/ae257.cfm" target="_blank">http://www.physlink.com/Education/AskExperts/ae257.cfm</a>

tronvillain · 08-09-2002, 10:26 PM

Interesting. Would that make it a theoretical possibility as well as a logical possibility? I'm not sure.

Answerer · 08-10-2002, 12:36 AM

What? Not even anti-matter have negative mass, so how can anything else have negative mass?

Friar Bellows · 08-10-2002, 02:17 AM

What is mass?

(sorry, I ask this question on a fairly regular basis, feel free to ignore it

)

Time&Task · 08-10-2002, 02:38 AM

Measurements for electron neutrino mass
The mass of electron neutrinos is measured in tritium beta decay experiments. The decay results in a 3-helium, electron and an electron antineutrino. If neutrinos have non-zero mass, the spectrum of the electrons is deformed at the high energy part, i.e. the neutrino mass determines the maximum energy of emitted electrons.

To be excact, the experiments measure the neutrino mass squared. Curiously, when taken at the face value, all results point to a negative mass squared, particularly the oldest experiment. This is probably due to a systematic error, and actually two running experiments, Mainz and Troitsk, have been able to measure physically acceptable values.

<a href="http://cupp.oulu.fi/neutrino/nd-mass.html" target="_blank">http://cupp.oulu.fi/neutrino/nd-mass.html</a>

Skepticwithachainsaw · 08-10-2002, 05:38 AM

I thought it was possible. In fact I thought you could get negative energy as well (and no, not the hippy variety...). <a href="http://www.physics.hku.hk/~tboyce/sf/topics/wormhole/wormhole.html" target="_blank">This old Scientific American had some stuff about it (yeah sorry it's "cheating" but I haven't got the time to write it all out in my own words...)</a>

I also thought that Hawking radiation (when a Black hole "evaporates") relayed on it, if anyone's got a copy of Brief History of Time handy have a look at it on page 116-118). Although it does imply that it is very rare for a negative energy particle to have a "Real existence" (real being as in the Real vs Virtual sense of particle physics)

Starboy · 08-10-2002, 10:50 AM

I suppose if there was such a thing it would have separated from the positive matter long ago. After all, they would repel each other.

Starboy

Demosthenes · 08-10-2002, 11:30 AM

negative energy exists, hence negative mass exists as well.

08-09-2002, 08:05 PM	#1
The Lost Number Junior Member Join Date: Jul 2002 Location: Somewhere in time Posts: 27	What about "Negative" matter? That is to say, matter which is (probably among other things) repellant to gravity. If dropped, it would "float up". Could this stuff exist anywhere in the universe? Can it be created, and if so, how? What would be the potential danger/s of it?

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08-09-2002, 09:22 PM	#2
tronvillain Veteran Member Join Date: Oct 2000 Location: Alberta, Canada Posts: 5,658	As far as I know, "negative matter" is not currently even a theoretical possibility, so to answer your questions: 1) No. Well, it is not a theoretical possibility, but it is a logical possibility, so I can't quite rule it out entirely. It's near enough that I can ignore the possibility though. 2) No. As I said it is not a theoretical possibility, so creating it pretty much out of the question. 3) None. Well, other than experiencing gravity negatively you have assigned it no properties so it is impossible to speculate on what dangers it might present if it did exist, which it doesn't.

08-09-2002, 10:10 PM	#3
NialScorva Veteran Member Join Date: Jan 2001 Location: Median strip of DC beltway Posts: 1,888	There are actually quite a few equations that can allow for negative mass, but no evidence as of yet for it. <a href="http://www.physlink.com/Education/AskExperts/ae257.cfm" target="_blank">http://www.physlink.com/Education/AskExperts/ae257.cfm</a>

08-09-2002, 10:26 PM	#4
tronvillain Veteran Member Join Date: Oct 2000 Location: Alberta, Canada Posts: 5,658	Interesting. Would that make it a theoretical possibility as well as a logical possibility? I'm not sure.

08-10-2002, 12:36 AM	#5
Answerer Veteran Member Join Date: Feb 2002 Location: Singapore Posts: 3,956	What? Not even anti-matter have negative mass, so how can anything else have negative mass?

08-10-2002, 02:17 AM	#6
Friar Bellows Veteran Member Join Date: Apr 2001 Location: arse-end of the world Posts: 2,305	What is mass? (sorry, I ask this question on a fairly regular basis, feel free to ignore it )

08-10-2002, 02:38 AM	#7
Time&Task Junior Member Join Date: Aug 2002 Location: Between This&That Posts: 5	Measurements for electron neutrino mass The mass of electron neutrinos is measured in tritium beta decay experiments. The decay results in a 3-helium, electron and an electron antineutrino. If neutrinos have non-zero mass, the spectrum of the electrons is deformed at the high energy part, i.e. the neutrino mass determines the maximum energy of emitted electrons. To be excact, the experiments measure the neutrino mass squared. Curiously, when taken at the face value, all results point to a negative mass squared, particularly the oldest experiment. This is probably due to a systematic error, and actually two running experiments, Mainz and Troitsk, have been able to measure physically acceptable values. <a href="http://cupp.oulu.fi/neutrino/nd-mass.html" target="_blank">http://cupp.oulu.fi/neutrino/nd-mass.html</a>

08-10-2002, 05:38 AM	#8
Skepticwithachainsaw Junior Member Join Date: Apr 2002 Location: In your Imagination Posts: 69	I thought it was possible. In fact I thought you could get negative energy as well (and no, not the hippy variety...). <a href="http://www.physics.hku.hk/~tboyce/sf/topics/wormhole/wormhole.html" target="_blank">This old Scientific American had some stuff about it (yeah sorry it's "cheating" but I haven't got the time to write it all out in my own words...)</a> I also thought that Hawking radiation (when a Black hole "evaporates") relayed on it, if anyone's got a copy of Brief History of Time handy have a look at it on page 116-118). Although it does imply that it is very rare for a negative energy particle to have a "Real existence" (real being as in the Real vs Virtual sense of particle physics)

08-10-2002, 10:50 AM	#9
Starboy Banned Join Date: Jun 2002 Location: Tallahassee, FL Reality Adventurer Posts: 5,276	I suppose if there was such a thing it would have separated from the positive matter long ago. After all, they would repel each other. Starboy

08-10-2002, 11:30 AM	#10
Demosthenes Veteran Member Join Date: Oct 2000 Location: a speck of dirt Posts: 2,510	negative energy exists, hence negative mass exists as well.

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