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Proposed Telescope Focuses Light Without Mirror Or Lens

helioquake Only advantage is the light weight (165 comments)

The article makes it sound like only a 30-meter "Fresnel" optics can allow to resolve an earth-size object within 30 light-years.

The fact is that any conventional 30-meter telescope can resolve an earth-size object within 30 light-years (circa 6000Angstrom in wavelength). Spatial resolution can be determined by the ratio of wavelength to diameter of the optics:

    6000A / 30m ~ 2e-8 radian ~ 0.004 arcsec.

So a 30m telescope can resolve an object in angular size of 0.004arcsec at 6000Angstrom.

At the distance of 30 light-years, the earth-size object looks like

    6400km / 30lyr ~ 2e-8 radian ~ 0.004 arcsec.

So that's that. This telescope doesn't give us any special resolving power per optics size. So the advantage is merely its light weight.

Since the precise alignment of holes is required for this optics to work, I can see why this project got kicked out by ESA. It's probably too premature to attempt in deploying this kind of precision engineering in space today.

more than 6 years ago


helioquake hasn't submitted any stories.



I love this new Slashdot Style!

helioquake helioquake writes  |  more than 8 years ago

I love this clean style that Slashdot has adopted. It's very easy to read now.


"Big Bang: it's just an opinion," says a NASA intern

helioquake helioquake writes  |  more than 8 years ago According to the article posted in NYT this morning, 24-yrs old political appointee, George Deutsch, at NASA claims that, I quote:

"The Big Bang is 'not proven fact; it is opinion,' Mr. Deutsch wrote, adding, 'It is not NASA's place, nor should it be to make a declaration such as this about the existence of the universe that discounts intelligent design by a creator.'"

He's a recent graduate of Texas A&M University with no advanced degree in science. He was one of the active campaign supporter of the current administration. Wonder no more how to earn a prestigeous NASA position without having strong science and engineering background!


Successful launch of Suzaku (Astro-E2)

helioquake helioquake writes  |  more than 9 years ago

The 2nd time is a charm...five years after the failure of the launch of ASTRO-E1, it's the time for redemption...that's what these good guys over ISAS (now JAXA) have done last night...ASTRO-E2/M-V-6 rocket was successfully launched from Uchinoura Space Center on 23:30 EDT, on July 9th, 2005, and has entered into the scheduled orbit. The separation of the satellite itself from the third stage has been confirmed also. The satellite is now officially named as "Suzaku" which is supposedly a bird god in the ancient Japanese folklore.

In a few days, we will know for sure if we have a newly functional X-ray astronomical observatory in space.

This mission is primarily supported by Japanese government, plus the unique mission instrument designed and provided by NASA/Goddard Space Flight Center, etc.


Religion is the worst human invention

helioquake helioquake writes  |  about 10 years ago

I'm agnostic. I know the difference between right and wrong. My parents told me three key things in life: don't steal; don't hurt; and be kind.

And now a question: if I am not a religious person, am I a bad person?

I cannot stand God's fan club: religion. Remember guys, RELIGION IS MAN-MADE CONCEPT. It is how fellow humans interpreted God's thought and will. Its ulterior motive is "perfected" by humans, not by God himself.

Again, I have no problem believing the existence of higher-power, or things and events we cannot describe in terms of science. But geez, I wouldn't want to take mere human's idea for granted. That just seems laughably ludicrous to me.


Why invest in science?

helioquake helioquake writes  |  about 10 years ago

I posted the following on Deep Impact thread:

Exploration and investment are the reasons for a mission like this.

The former -- exploration -- is what NASA and scientists will advertise in front. Why? Because we know so little about comets. Imagine, if the judgement day comes and we have to "shoot down" one of these in order to save the humanity, wouldn't you be rather comfortable to know what and how comets are really made of? We really do not know what happens to a comet when we toss a stick of dynamite into it, as its structural integrity is not well known.

The latter -- investment -- is the second and the foremost important reason. In order for a super-power nation to sustain its technological supremacy in this world, its government must invest its money for the advancement of engineering and science [*]. The investment to a NASA's mission like this may not seem as important as an investment toward curing cancer, etc., but such assessment is near-sighted. For example, building of a scientific instrument requires a miniaturization of electronic component (in order to reduce its size and weight). Each component is also certified to withstand harsh cosmic environment (sudden changes in temperature and severe bombardment by cosmic radiation). The skills learned through these R&D may eventually trickle down to the industry, and hence possibly leading to development of affordable high-tech components (e.g., IC chips in a decade ago). Basically the high cost of R&D may be paid by the government and the industry would benefit from such learned knowledge. It is not too surprising that a medical breakthrough on cancer may come from the spread of affordable technology obtained through space research.

[*] There was no time in history that a single nation had dominated the world without its technological advantage.

But at the bottom line, the choice is up to you and other constituents in the nation. You ask your representatives to choose either to feed the hungry right now or to invest on the future. I'm inclined to choose the latter.

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