1234 replies to this topic

[Time_Traveller]

Distant 'waterworld' is confirmed



Astronomers have confirmed the existence of a new class of planet: a waterworld with a thick, steamy atmosphere.

The exoplanet GJ 1214b is a so-called "Super Earth" - bigger than our planet, but smaller than gas giants such as Jupiter.

From http://www.bbc.co.uk...onment-17117030

[mic of orion]

New Type of Alien Planet Is a Steamy 'Waterworld'




Scientists have discovered a new type of alien planet — a steamy waterworld that is larger than Earth but smaller than Uranus.

The standard-bearer for this new class of exoplanet is called GJ 1214b, which astronomers first discovered in December 2009. New observations by NASA's Hubble Space Telescope suggest that GJ 1214b is a watery world enshrouded by a thick, steamy atmosphere.

"GJ 1214b is like no planet we know of," study lead author Zachory Berta of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., said in a statement. "A huge fraction of its mass is made up of water."
Adding to the diversity

To date, astronomers have discovered more than 700 planets beyond our solar system, with about 2,300 more "candidates" awaiting confirmation by follow-up observations.



These alien planets are a diverse bunch. Astronomers have found one planet as light and airy as Styrofoam, for example, and another as dense as iron. They've discovered several alien worlds that orbit two suns, like Luke Skywalker's home planet of Tatooine in the "Star Wars" films. [The Strangest Alien Planets]

But GJ 1214b, which is located 40 light-years from Earth in the constellation Ophiuchus (The Serpent Bearer), is something new altogether, researchers said.

This so-called "super-Earth" is about 2.7 times Earth’s diameter and weighs nearly seven times as much as our home planet. It orbits a red-dwarf star at a distance of 1.2 million miles (2 million kilometres), giving it an estimated surface temperature of 446 degrees Fahrenheit (230 degrees Celsius) — too hot to host life as we know it.

Scientists first reported in 2010 that GJ 1214b's atmosphere is likely composed primarily of water, but their findings were not definitive. Berta and his team used Hubble's Wide Field Camera 3 to help dispel the doubts.

Hubble watched as GJ 1214b crossed in front of its host star, and the scientists were able to determine the composition of the planet's atmosphere based on how it filtered the starlight.

"We’re using Hubble to measure the infrared color of sunset on this world," Berta said. "The Hubble measurements really tip the balance in favor of a steamy atmosphere."

Berta and his colleagues report their results online in the Astrophysical Journal.

A watery world

Since astronomers know GJ 1241b's mass and size, they're able to calculate its density, which turns out to be just 2 grams per cubic centimeter (g/cc). Earth's density is 5.5 g/cc, while that of water is 1 g/cc.

GJ 1214b thus appears to have much more water than Earth does, and much less rock. The alien planet's interior structure is likely quite different from that of our world.

"The high temperatures and high pressures would form exotic materials like 'hot ice' or 'superfluid water,' substances that are completely alien to our everyday experience," Berta said.

GJ 1214b probably formed farther out from its star, where water ice was plentiful, and then migrated in to its current location long ago. In the process, it would have experienced more Earth-like temperatures, but how long this benign phase lasted is unknown, researchers said.

Because GJ 1214b is so close to Earth, it's a prime candidate for study by future instruments. NASA's James Webb Space Telescope, which is slated to launch in 2018, may be able to get an even better look at the planet's atmosphere, researchers said. http://i.space.com/i....jpg?1329836948

[Time_Traveller]

'Marsquake' May Have Shaken Up Red Planet

The surface of Mars appears to have been shaken by quakes relatively recently, hinting at the existence of active volcanoes and perhaps reservoirs of liquid water on the Red Planet, a new study suggests.

From http://www.space.com...quid-water.html

[wjfox]

MPs warn over nuclear space bombs and solar flares

The government must take more seriously the threat of a nuclear weapon being exploded in space by a rogue state, MPs have warned.

The Defence Select Committee said the resulting radiation pulse could disrupt power and water supplies, UK defence and satellite navigation systems.

Its chairman, Tory MP James Arbuthnot, said an attack was "quite likely".

http://www.bbc.co.uk...litics-17117836

[Craven]

Quite likely? Oh please...

I fear this can impede use of nuclear technology in space exploration even further.

[mic of orion]

Going up: Japan builder eyes space elevator


A Japanese construction firm claimed Wednesday it could execute an out-of-this-world plan to put tourists in space within 40 years by building an elevator that stretches a quarter of the way to the moon.

Obayashi Corp claims it could use carbon nanotube technology, which is more than 20 times stronger than steel, to build a lift shaft 96,000 kilometres (roughly 60,000 miles) above the Earth.

The company said it would carry up to 30 passengers at a time and travel at a speed of 200 kilometres per hour for a week, stopping off at a station at 36,000 kilometres.

Tourists would stay there, but researchers and specialists would be able to travel all the way to the end, said Satomi Katsuyama, the project's leader.

"Humans have long adored high towers," she said. "Rather than building it from the earth, we will construct it from the space."

However, while Obayashi says the plan could work, there are presently no estimates for the cost of the structure, nor any idea where to build it, or who would pay for it.

Obayashi is just days away from completing work on Japan's tallest structure, the Tokyo Sky Tree, which will stand 634 metres (2,080 feet).

The tower will serve as a digital broadcasting antenna as well as a sightseeing attraction that allows uninterrupted views of the Japanese capital and beyond.

"We were inspired by construction of Sky Tree," which will open for business in May, she said. "Our experts on construction, climate, wind patterns, design, they say it's possible."

When Obayashi is not drawing up plans to conquer space it works on a number of projects from building corporate headquarters, bridges and power plants to renovating ancient temples.

Among its portfolio are the Dubai Metro in United Arab Emirates, Universal Studios Osaka, Japan, and Stadium Australia, which was used for the Sydney Olympics.
http://www.physorg.c...e-elevator.html

Interesting far fetched story, hope you don't mind me sharing with you.

[mic of orion]

Sheep in Wolf-Rayet's Clothing: New Image of Planetary Nebula Hen 3-1333

It's well known that the universe is changeable: even the stars that appear static and predictable every night are subject to change.



A new image from the NASA Hubble Space Telescope shows planetary nebula Hen 3-1333. Planetary nebulae have nothing to do with planets -- they actually represent the death throes of mid-sized stars like the sun. As they puff out their outer layers, large, irregular globes of glowing gas expand around them, which appeared planet-like through the small telescopes that were used by their first discoverers.

The star at the heart of Hen 3-1333 is thought to have a mass of around 60% that of the sun, but unlike the sun, its apparent brightness varies substantially over time. Astronomers believe this variability is caused by a disc of dust which lies almost edge-on when viewed from Earth, which periodically obscures the star.

It is a Wolf-Rayet-type star -- a late stage in the evolution of sun-sized stars. These are named after (and share many observational characteristics with) Wolf-Rayet stars, which are much larger. Why the similarity? Both Wolf-Rayet and Wolf-Rayet type stars are hot and bright because their helium cores are exposed: the former because of the strong stellar winds characteristic of these stars; the latter because the outer layers of the stars have been puffed away as the star runs low on fuel.

The exposed helium core, rich with heavier elements, means that the surfaces of these stars are far hotter than the sun, typically 25,000 to 50,000 degrees Celsius (45,030 to 90,030 Fahrenheit). The sun has a comparatively chilly surface temperature of just 5,500 degrees Celsius (9,932 Fahrenheit).

So while they are dramatically smaller in size, the Wolf-Rayet type stars such as the one at the core of Hen 3-1333 effectively mimic the appearance of their much bigger and more energetic namesakes: they are sheep in Wolf-Rayet clothing.

This visible-light image was taken by the high resolution channel of Hubble's Advanced Camera for Surveys. The field of view is approximately 26 by 26 arcseconds.

http://www.scienceda...20220144413.htm

Edited by mic of orion, 22 February 2012 - 05:21 PM.

[Craven]

Going up: Japan builder eyes space elevator

Interesting far fetched story, hope you don't mind me sharing with you.

Well it may not be that far fetched, it's just damn hard and troublesome.

[truthiness]

However, while Obayashi says the plan could work, there are presently no estimates for the cost of the structure, nor any idea where to build it, or who would pay for it.

This is a good point... Where would we build a space elevator?

It'd have to be on the equator someplace, but almost everywhere on the equator isn't what you call ideal. Unless you want it anchored in the ocean (which seems to me to be an engineering problem in and of itself), you've really got three choices - a band of chronically unstable countries in Africa, equally tectonically unstable Indonesia, and a few countries in South America. Of those countries in South America, I'd look at two - Ecuador and Brazil. Ecuador's capital, Quito, is very close to the equator and is already at 9,200 feet above sea level. So, a bit of a head start. But, Ecuador also has seismic trouble, and Quito itself lies in the shadow of an active volcano. I think any space elevator we build should be built to last. So, Brazil. Brazil is a big country with plenty of good places for a super-project, but the entire part of Brazil that is actually on the equator is also deep in the Amazon rainforest. The Amazon river delta is itself on the equator. Not sure if that's the sort of place where a massive construction project or transportation terminal should be set up.

So, where should we build a space elevator, then?

Edited by truthiness, 23 February 2012 - 03:09 AM.

[Roh234]

Why would we need to but the base at the equator? With a bit of Trig and Calculus (which I assume it will be easy for the the scientists for this project), the altitude and velocity required for such a place. The debate would then be where would it be located? New York, L.A, London, Paris, Moscow, Stockholm, Bejing, Shanghai, New Delhi, Mumbai, Bejing, Sao Paulo, Toyoko?

The problems I have is the magnetic field. Remember 1996 where the theater melted due to the current induced by the Earth's Magnetic field. And 200km/h, it should atleast be 1000km/h to be attractive to the public? I don't know if anyone wants to stay in a crammed elavator for a week to go up and a week to go down. If anyone has been in an airplane, the temp drops fast as one gains altitude. The heating costs. maybe some of this could be solved with a copper/silver coating to channel electricity for heating and utilities. But it really doesn't grab my mind.

That's just the basic concerns I have.

[truthiness]

Hm... I've never heard of a proposal that didn't place the Earthbound anchor at or very near the equator. Here is one expert's point of view on the subject. (the relevant question is about halfway down). He says it'll have to be within 20 degrees of the equator, and that the farther you get from the equator, the shorter the lifespan of your elevator.

http://www.pbs.org/w...s-elevator.html

Another idea would be to have two elevators that share an anchor in space. Each elevator would have an anchor on Earth at opposite positions relative to the equator. This idea does open up a few new options, but not as many as you might think. You could link up the east coast of the US with somewhere in Chile, or Eastern China with Western Australia. Europe would be out of luck, though, unless a tether is set up somewhere in Egypt while the other side is in South Africa. I think this idea would be best, but of course it would require the construction of two elevators instead of one. That's a pretty big drawback, even if they could be built in more heavily populated and more stable areas.

[Craven]

Unless you want it anchored in the ocean (which seems to me to be an engineering problem in and of itself),

It's more like opportunity than problem. At this moment it seems impossible to anchor space elevator to ground, it simply HAS to be placed in ocean.

Why would we need to but the base at the equator?

Centrifugal force.

And 200km/h, it should atleast be 1000km/h to be attractive to the public? I don't know if anyone wants to stay in a crammed elavator for a week to go up and a week to go down.

Yeah, totally. Could you also tell us your demands concerning menu?

We're talking about 20-fold or even 50-fold reduction of costs of bringing payload to geostationary orbit.
Also about re-entry - crawlers/climbers would probably be designed to jump down to earth after climb, so it would be faster.

Edited by Craven, 23 February 2012 - 12:22 PM.

[Roh234]

I'm talking if the Earth's magnetic field can cause this:
http://www-istp.gsfc...on/wtether.html

And the equator maybe this will help:


I'm all good with a space elevator but it has to be though out. At least if man is going to create a 35k km structure going into the atmosphere and costing at $10bn (estimates) but I really estimate it to be at $300bn. Its going to be a lot more dangerous working on this:

[Craven]

1. Do you think that people planning such construction wouldn't know about attributes of Earth's magnetic field?

2. I don't see your point in posting plate tectoincs/volcanoes map. I'm quite sure that you know that not whole equator is burning stripe of lava.

3. Seriously? You bring up photo from 1932 construction site? Irrevelant would be an understatement.

[Time_Traveller]

Nomad Alien Planets May Fill Our Milky Way Galaxy



Our Milky Way galaxy may be teeming with rogue planets that ramble through space instead of being locked in orbit around a star, a new study suggests.

These "nomad planets" could be surprisingly common in our bustling galaxy, according to researchers at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), a joint institute of Stanford University and the SLAC National Accelerator Laboratory. The study predicts that there may be 100,000 times more of these wandering, homeless planets than stars in the Milky Way.

From http://www.space.com...ing-galaxy.html

[Time_Traveller]

Extending the Habitable Zone for Red Dwarf Stars




Stars known as red dwarfs might have larger habitable zones friendly to 'life as we know it' than once thought, researchers say.

Red dwarfs, also known as M stars, are dim compared to stars like our sun and just 10 to 20 percent as massive. They make up roughly three-quarters of the stars in the galaxy, and recently scientists found red dwarfs are far more common than before thought, making up at least 80 percent of the total number of stars.

From http://www.spacedail..._Stars_999.html

[Craven]

Also, young red dwarfs less than 3 billion years old may be very active, firing off flares several times per day, causing ultraviolet radiation to jump by 100 to 10,000 times normal levels and potentially sterilizing the surface of a nearby planet or even helping to strip off its atmosphere.

That's most interesting bit for me. Even if after 3bn years star is no longer active to such extend, what if by that time it has no atmosphere?

Also I wonder if planets in this updated habitable zone will also be tidally locked.

[Roh234]

I just feel more work is needed on the magnetic field.

I just feel that we are not ready till mid century. I don't think today's tech could handle a space elevator nor will it be the $10 bn especially if we want a mobile oceanic base.

And the 1932 pic, I couldn't find a dangerous picture of a space operation.

[mic of orion]

Also, young red dwarfs less than 3 billion years old may be very active, firing off flares several times per day, causing ultraviolet radiation to jump by 100 to 10,000 times normal levels and potentially sterilizing the surface of a nearby planet or even helping to strip off its atmosphere.

That's most interesting bit for me. Even if after 3bn years star is no longer active to such extend, what if by that time it has no atmosphere?

Also I wonder if planets in this updated habitable zone will also be tidally locked.

red dwarfs in main sequence tend to have life span on between 500 billion and several trillion years. Example Proxima with its mass is set to last at least 2.4 trillion years of which in main sequence at least 2.3 trillion years.

in other words 3bn for a red dwarf is nothing, Once Red Dwarfs enter main sequence stage they are very stable but still very much active, article is bit misleading and confusing.

Flare stars (also traditionally red dwarfs, tend to have heightened coronal activity level and thus might not be most suitable hosts for life on a planet that might orbit the star in habitable orbit.

Edited by mic of orion, 25 February 2012 - 02:03 AM.

[Craven]

My point is, if atmosphere is blown away in first 3bn years, lifespan of star is not really important, as planet no longer will be habitable.

@Roh234 - we need more work in more fields that you'd think, but that's totally normal with such crazy project.