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Fuck yeah, Science!

It's the Hubble Space Telescope's Birthday. Enjoy Amazing Images Of The Lagoon Nebula


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Play the video on full screen on your computer if you can (doesn't seem to work from here on my computer, but it does if you follow the link above to the NPR story):

 
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This seems significant - an underwater lake was found on Mars:

 
A sorta sad note in the science world
The Final Report from the Mars Exploration Rovers (MER) mission has been posted.

http://http://www.planetary.org/explore/space-topics/space-missions/mer-updates/2019/03-mer-update-the-final-report.html

Spirit and Opportunity did some incredible science on Mars and long outlived their nominal life expectancy.

Opportunity was stopped by a massive dust storm June 10, 2018. She has not responded since and NASA had ceased attempts at communication. She made 5354 Martian sols. Pretty good for something designed for 90.

Her sister, Spirit, last responded in 2011.

Both were launched in the summer of 2003 and arrived on Mars in early 2004. Incredible runs for both. Both achieved incredible science, beyond even the wildest dreams of the NASA and JPL investigators. Endings are sad, but it is hard to feel too bad about the end of the MER Mission with all that was accomplished.

ETA:

Part of the legacy from Spirit and Opportunity is over 7.5 Terabytes of data, including thousands of photographs and the travelogue of over 32 miles on the surface of Mars. All this is available to the public, as it had been throughout the mission.
 
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One again former administrations have left a mess for Trump to clean up.
 
 
Perseverance on its way! Lift off was right on schedule at 7:50 AM EDT. Gorgeous weather. Atlas flight was perfect.
 
Space nerd needed to straighten me out:

I'm probably wrong but as I understand how these things travel to Mars, or wherever, is they get up in zero gravity, get some momentum (slingshot around the earth or something like that) and just coast to where they are going and using some gas/air pressure exhausts to slow down or correct course.
If you took a space shuttle up, like they used to, and had the cargo bay filled with fuel and then "floored it" towards Mars and keep going until it runs out of fuel I'm guessing it would be hauling ass like we've never seen given zero gravity. Slowing down might be a problem :)
Is this what they are doing anyway but on a smaller scale?
 
Blood test may be able to detect cancer up to 4 years before symptoms occur

https://www.scientificamerican.com/...ncer-up-to-four-years-before-symptoms-appear/

Added from someone per reddit:

I actually work with these tests and it's the new big thing in cancer detection. Cell-free DNA detected in the blood plasma can be collected. When cells die off they release DNA into the bloodstream, having a half life of around only 30 minutes. Very, very short. If you have a small tumour, well-connected to the blood stream, the cells will die at a higher rate. That higher rate of cell death, via apoptosis or necrosis will increase the levels of cell-free DNA in your blood plasma. That's the first sign. Then if you create a targetted panel of genes to cancer, you can match up your cell-free DNA to detect mutations being given off.

This method, should it continue to prove good, will help cancer screening. Many tumours can't be imaged until they are big enough, or a biopsy may be too difficult or dangerous to take.
 
Space Station astronauts due to return Sunday. Hurricane may delay their return. Tough to land on an ocean that is churned up by a hurricane.
 
Space nerd needed to straighten me out:

I'm probably wrong but as I understand how these things travel to Mars, or wherever, is they get up in zero gravity, get some momentum (slingshot around the earth or something like that) and just coast to where they are going and using some gas/air pressure exhausts to slow down or correct course.
If you took a space shuttle up, like they used to, and had the cargo bay filled with fuel and then "floored it" towards Mars and keep going until it runs out of fuel I'm guessing it would be hauling ass like we've never seen given zero gravity. Slowing down might be a problem :)
Is this what they are doing anyway but on a smaller scale?

Spacecraft need to exceed 25,000 mph to leave earth orbit. Believe it not, the gravity of the sun slows spacecraft as they go away from the sun. The Perseverance craft was traveling about 26,000 mph leaving earth's gravity. It has a small amount of fuel to use for steering/course correction during the coast or cruise phase. It does not use a "slingshot" gravity assist. All the velocity it has it got from the Atlas V/Centaur launch vehicle.

Other spacecraft, going further out in the solar system, have used gravity assist by flying near other planets. Jupiter is a favorite for spacecraft going to outer planets because it is really massive and gives a nice velocity boost.

Interesting thought on the shuttle. However, let me inject a little reality. The shuttle cargo capacity is actually fairly small, about 65,000 pounds. The Atlas V which launched Perseverance had 4 solid rocket boosters (SRB) attached. Each of those had 100,000 pounds of solid rocket fuel. The Atlas can fly with up to five SRB. The shuttle external fuel tank carried about 1.6 million pounds of fuel and oxygen. So just filling the shuttle cargo bay wouldn't get you much added fuel/oxygen to add to velocity.

An Atlas V with 5 SRB launched the Pluto/New Horizon spacecraft. It reached the velocity of over 36,000 mph leaving earth. In less than 9 hours it was past the orbit of the moon. It took the Apollo astronauts between two and three days to make the trip to the moon.

The Perseverance craft will be traveling about 13,000 mph upon entering the atmosphere of Mars. (Because the gravity of the sun will slow it that much.) It will slow down using the Martian atmosphere, just like re-entering capsules use the earth's atmosphere. There is a giant heat shield to protect the rover. Then it will deploy parachutes to slow down further, and finally use a rocket powered "sky crane" to slow to about 1 mph for final landing.
 
Spacecraft need to exceed 25,000 mph to leave earth orbit. Believe it not, the gravity of the sun slows spacecraft as they go away from the sun. The Perseverance craft was traveling about 26,000 mph leaving earth's gravity. It has a small amount of fuel to use for steering/course correction during the coast or cruise phase. It does not use a "slingshot" gravity assist. All the velocity it has it got from the Atlas V/Centaur launch vehicle.

Other spacecraft, going further out in the solar system, have used gravity assist by flying near other planets. Jupiter is a favorite for spacecraft going to outer planets because it is really massive and gives a nice velocity boost.

Interesting thought on the shuttle. However, let me inject a little reality. The shuttle cargo capacity is actually fairly small, about 65,000 pounds. The Atlas V which launched Perseverance had 4 solid rocket boosters (SRB) attached. Each of those had 100,000 pounds of solid rocket fuel. The Atlas can fly with up to five SRB. The shuttle external fuel tank carried about 1.6 million pounds of fuel and oxygen. So just filling the shuttle cargo bay wouldn't get you much added fuel/oxygen to add to velocity.

An Atlas V with 5 SRB launched the Pluto/New Horizon spacecraft. It reached the velocity of over 36,000 mph leaving earth. In less than 9 hours it was past the orbit of the moon. It took the Apollo astronauts between two and three days to make the trip to the moon.

The Perseverance craft will be traveling about 13,000 mph upon entering the atmosphere of Mars. (Because the gravity of the sun will slow it that much.) It will slow down using the Martian atmosphere, just like re-entering capsules use the earth's atmosphere. There is a giant heat shield to protect the rover. Then it will deploy parachutes to slow down further, and finally use a rocket powered "sky crane" to slow to about 1 mph for final landing.

Thanks. This was very helpful. So "what if" The Perseverance had a really large fuel tank that is not needed to get it into orbit. At 5:0 pm today it turns them on and exhausts the fuel tank (say that takes 3 minutes). Couldn't you approach speeds up to say 250,000 - 500,000 mph? You probably would not do this for crafts that eventually will try to land on a planet but of you are just sending one out to do flybys, take pictures and see how deep you can travel into space it might be cool. Seems like if you have enough fuel (and large enough engine) and almost no atmospheric drag you could, in theory, approach the speed of light. Or is it the zero oxygen in space that keeps traditional engines for working the same way as they do on earth?
 
Thanks. This was very helpful. So "what if" The Perseverance had a really large fuel tank that is not needed to get it into orbit. At 5:0 pm today it turns them on and exhausts the fuel tank (say that takes 3 minutes). Couldn't you approach speeds up to say 250,000 - 500,000 mph? You probably would not do this for crafts that eventually will try to land on a planet but of you are just sending one out to do flybys, take pictures and see how deep you can travel into space it might be cool. Seems like if you have enough fuel (and large enough engine) and almost no atmospheric drag you could, in theory, approach the speed of light. Or is it the zero oxygen in space that keeps traditional engines for working the same way as they do on earth?

In reverse order of your questions, a spacecraft needs to carry both fuel and oxygen, because, as you noted there is no oxygen in space. Thus the liquid fuel in rocket boosters is often Rocket Propellant 1 (RP-1) and liquid oxygen. Yes, the engines in spacecraft are different from engines used on earth, because on earth we have lots of oxygen available in the air. Solid rocket fuel has both fuel and oxidizer in solid form.

The issue with "having a great big fuel tank" is that you have to get all that mass off the earth . You would need to burn a lot of fuel to get the fuel moving. That is why there is interest in developing a fuel production facility on the moon. Much less gravity to fight to get out of earth orbit.

Be prepared for calculus!

Website with decent calculation of the energy requirements

The bottom line from the website:

So, for a rocket with a payload of 2 tonnes to escape from Earth with an exhaust velocity of 5 km/s, we require m_i – m_f = 1.871 \cdot 10^4 – 2,000 = 1.671 \cdot 10^4 \approx 17 \text{ tonnes}mi​–mf​=1.871⋅104–2,000=1.671⋅104≈17 tonnes of fuel. That is roughly 90\%90% of the total initial mass of the rocket!


To get two tons of "payload" (in your example, a fuel tank) to escape velocity, you need to burn 17 tons of fuel. To get 100,000 pounds (50 tons) of fuel to escape velocity would require 425 tons (850,000 pounds) of fuel.

For perspective, the Saturn V, so far the biggest rocket ever built, could get 107,000 lbs to the moon.
 
OK so you win with this science stuff :) I guess I need to go dig up some dilithium crystals and conduct my own experiment. I'll keep you posted.
Seriously thanks for the feedback.
 
OK so you win with this science stuff :) I guess I need to go dig up some dilithium crystals and conduct my own experiment. I'll keep you posted.
Seriously thanks for the feedback.

I was going to ask Blue how much energy it would take to slingshot around the sun to time travel from the late 23rd century to the 1980s but figured he'd just say "dilithium crystals" and be done with it.
 
OK so you win with this science stuff :) I guess I need to go dig up some dilithium crystals and conduct my own experiment. I'll keep you posted.
Seriously thanks for the feedback.

I was going to ask Blue how much energy it would take to slingshot around the sun to time travel from the late 23rd century to the 1980s but figured he'd just say "dilithium crystals" and be done with it.

I was planning on doing this, but when I tried to open my dilithium crystal energetics calculator I got a "file not found" error message. The calculation will have to wait intil it is found.
 
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