Would an ETV be able to visit Earth secretly?

[Erno86]

 

20 hours ago, freetoroam said:

Finding life on another planet for us does not need a man in a spaceship...so it is possible an alien inhabitated craft is not on its way to us, but an alien un(manned) craft and it relays back images of what it discovers on its way...(like Cassini did for us) then being detected would not be an issue. 

 

 

Why send a robot to do a human's job?

Just put yourself in a ET civilization's place, who just might want to sent a probe to our planet that involved only just robots. Do you think they would they really want to take a chance on that? I mean...what if these robots fell into the wrong hands, or just went bonkers against another species with no realistic chance of controlling these robots from light years away? I'll take my odds that they would send sentient alien beings for first contact, and only use robots as servants for the boss man; whether in hazardous or life threatening situations --- thank-you!!!

[Fila]

On 02/01/2018 at 10:58 PM, freetoroam said:

When i say the skies are being watched, this includes all means, not just with a human eye.

Astronomers don't stare at the sky.., or stare through a telescope for hours scanning the sky.

When Astronomers are looking through a telescope, zoomed in on a fixed location, which covers a tiny percentage of a distant part of outer space.., they look, observe the distant star formations.., and record the data.

The UFO phenomenon is more localised, generally reported being 7000 ft and under..,  which would be like moving a pen or even a hand past a pair binoculars, and you see nothing but a blur (if that) as if the hand did not pass by the binoculars at all. They also do not see 100% coverage of the sky.., its like a pin hole in a piece of paper, but focused way out into space. This is why someone standing outside the observatory would see a UFO, but the astronomer didn't (but could see Venus, therefore it was Venus).

Astronomers do not really look through telescopes as much as everybody thinks. This is more of a romanticised version of what we think happens. the very few remote stations are accessed via SSH or VNC on a computer wherever you live.

Competition for telescope time is fiercely prioritised. Even if you as an astronomer managed to snag 2 hours next week, you would be focused on your specific task of studying a distant solar system's planet wobble past it's sun, or whatever your project is.

Edited January 2, 2018 by Fila

[stereologist]

On 1/1/2018 at 2:07 PM, Erno86 said:

I'd imagine...to a point, since the otherworlders that  occasionally visit our planet obviously have the capability of magnetically shielded  plasma stealth technology surrounding there starships at certain times, where the plasma shield simply absorbs radar and sound waves.

The only probable drawback using this technology...is that the plasma makes them visible, especially during nighttime. Though they might operate on some kind of impulse power where the plasma shield can be turned off an on at will, while still having residual power for there starship during nighttime OP's. During daylight...when the sun is out --- it might be no reason for the alien starship to turn to plasma stealth, because they can probably easily out-fly us; while relying on the sun as a possible energy source for photon propulsion.

Flying below radar cover is always an option...

I assume this is not meant to be real, the "magnetically shielded  plasma stealth technology surrounding there starships"

A plasma would be a reflective surface. EM theory shows that a conductor/insulator interface reflects. That is what a mirror does. Plasma is a conductor. A plasma would not be a good absorber.

https://en.wikipedia.org/wiki/Plasma_(physics)

https://en.wikipedia.org/wiki/Signal_reflection

[stereologist]

22 hours ago, Fila said:

Thank you for your reply Seeder. I'll have to reply to your post 1 item at a time. We can start from deep space if you'd like.., and work back to closer technology.

The fact that we can see asteroids in space.., does make it seem like we can detect everything all the time. I also used to assume this until I looked into how it all works. Observers find and track NEOs using NASA’s space-based NEOWISE infrared telescope and ground-based telescopes around the world which can;

 

There are a number of devices that search for NEOs. Pan-Starrs can find NEOs. So can LINEAR.

https://www.ll.mit.edu//mission/space/linear/

https://en.wikipedia.org/wiki/Pan-STARRS

The last link mentions other NEO finding devices.

[Erno86]

9 minutes ago, stereologist said:

I assume this is not meant to be real, the "magnetically shielded  plasma stealth technology surrounding there starships"

A plasma would be a reflective surface. EM theory shows that a conductor/insulator interface reflects. That is what a mirror does. Plasma is a conductor. A plasma would not be a good absorber.

https://en.wikipedia.org/wiki/Plasma_(physics)

https://en.wikipedia.org/wiki/Signal_reflection

If there's any reverse-engineering going on by us...its highly probable that it's plasma stealth technology!!!

"Plasma Stealth"

"Plasma stealth is a proposed process to use ionized gas (plasma) to reduce the radar cross section (RCS) on an aircraft."

 

https://en.wikipedia.org/wiki/Plasma_stealth

[stereologist]

21 hours ago, Fila said:

If an advanced ET race can traverse the galaxy.., I would assume they have had to figure out how to re-enter their atmosphere and others. Its a pretty big priority if you plan on going up. We humans sorted it out very quickly, at its not really "rocket science". Just a heat shield and high altitude parachutes

The issue with the low angle entry is not about burning up in the atmosphere. It has to do with the deceleration of the craft. Come into the atmosphere at too high an angle and the craft slows down too fast. The G-forces would crush the occupants. Come in at too low an angle and the craft can "skip off" our atmosphere. The spacecraft returning to Earth do not have the ability to do a second try.

[Fila]

On 03/01/2018 at 8:18 AM, stereologist said:

There are a number of devices that search for NEOs. Pan-Starrs can find NEOs. So can LINEAR.

https://www.ll.mit.edu//mission/space/linear/

https://en.wikipedia.org/wiki/Pan-STARRS

The last link mentions other NEO finding devices.

Thanks. The LINEAR is not currently being used for NEOs.., but tested. They have 2 devices for optical deep space viewing. This would only cover 40% of the Northern Hemisphere, only at night, with no cloud cover. Subject to damage, repairs and updates reducing the 100% 24/7 coverage drastically.

The device uses one CCD (Charged Couple Device).., which are found in modern camera's (my SONY had 3 CCD's). Its an optical scope.., used only at night time that sends data back to a computer to "generate" observations. The same process is used.., where single images are taken and compared over many nights of data to make an "observation". Nothing is detected LIVE as we would assume.

Pan-Starr is cool, but also uses the same slow technique of "detecting differences from previous observations of the same areas of the sky, " over days and weeks to make an observation.

Basically.., something could fly past all these devices and never be seen. There just not as LIVE as we think they are.

Edited January 2, 2018 by Fila

[stereologist]

37 minutes ago, Fila said:

Astronomers don't stare at the sky.., or stare through a telescope for hours scanning the sky.

When Astronomers are looking through a telescope, zoomed in on a fixed location, which covers a tiny percentage of a distant part of outer space.., they look, observe the distant star formations.., and record the data.

The UFO phenomenon is more localised, generally reported being 7000 ft and under..,  which would be like moving a pen or even a hand past a pair binoculars, and you see nothing but a blur (if that) as if the hand did not pass by the binoculars at all. They also do not see 100% coverage of the sky.., its like a pin hole in a piece of paper, but focused way out into space. This is why someone standing outside the observatory would see a UFO, but the astronomer didn't (but could see Venus, therefore it was Venus).

Astronomers do not really look through telescopes as much as everybody thinks. This is more of a romanticised version of what we think happens. the very few remote stations are accessed via SSH or VNC on a computer wherever you live.

Competition for telescope time is fiercely prioritised. Even if you as an astronomer managed to snag 2 hours next week, you would be focused on your specific task of studying a distant solar system's planet wobble past it's sun, or whatever your project is.

Your idea of how astronomers work is rather limited. As I've mentioned in other threads there are wide field telescopes. Your comment about "covers a tiny percentage of a distant part of outer space" disregards these very important types of telescopes.

Here is a discussion concerning these scopes: https://stargazerslounge.com/topic/83925-wide-field-telescope/

These types of scopes are commonly used in surveys of the night sky.

[Erno86]

Sterologist -

"Boeing's 'plasma shields' would block explosion shockwaves."

https://www.engadget.com/2015/03/23/boeing-plasma-shield/

[stereologist]

16 minutes ago, Erno86 said:

If there's any reverse-engineering going on by us...its highly probable that it's plasma stealth technology!!!

"Plasma Stealth"

"Plasma stealth is a proposed process to use ionized gas (plasma) to reduce the radar cross section (RCS) on an aircraft."

 

https://en.wikipedia.org/wiki/Plasma_stealth

It uses the plasma as a converter and reduces the RCS while increasing other wavelength discharges. Would aliens bother to deal with radar?

[stereologist]

Just now, Erno86 said:

Sterologist -

"Boeing's 'plasma shields' would block explosion shockwaves."

https://www.engadget.com/2015/03/23/boeing-plasma-shield/

There are plenty of suggestions and that one is completely irrelevant.

[stereologist]

9 minutes ago, Fila said:

Thanks. The LINEAR is not currently being used for NEOs.., but tested. They have 2 devices for optical deep space viewing. This would only cover 40% of the Northern Hemisphere, only at night, with no cloud cover. Subject to damage, repairs and updates reducing the 100% 24/7 coverage drastically.

The device uses one CCD (Charged Couple Device).., which are found in modern camera's (my SONY had 3 CCD's). Its an optical scope.., used only at night time that sends data back to a computer to "generate" observations. The same process is used.., where single images are taken and compared over many nights of data to make an "observation". Nothing is detected LIVE as we would assume.

Pan-Starr is cool, but also uses the same slow technique of "detecting differences from previous observations of the same areas of the sky, " over days and weeks to make an observation.

Basically.., something could fly past all these devices and never be seen. There just not as LIVE as we think they are.

I think you are missing the important message in both cases. Your idea of how astronomers work is wrong. That is why I wrote my post as I did. You need to learn how astronomy is run. I never suggested or stated anything other than your idea of astronomy is wrong.

[stereologist]

As far as can an object return to Earth without detection? EASILY.

It happens thousands of times a day. Fireballs, really bright meteors, enter the atmosphere thousands of times a day. They are not seen. The problem is that 69% of the Earth is water. There  is no land out there and we monitor the land. Ground based observations miss almost all of the fireballs which are really spectacular.

If I were trying to scoot into the Earth's atmosphere unnoticed I'd try the polar regions or the Pacific.

 

[Fila]

On 03/01/2018 at 8:47 AM, stereologist said:

Your idea of how astronomers work is rather limited. As I've mentioned in other threads there are wide field telescopes. Your comment about "covers a tiny percentage of a distant part of outer space" disregards these very important types of telescopes.

Here is a discussion concerning these scopes: https://stargazerslounge.com/topic/83925-wide-field-telescope/

These types of scopes are commonly used in surveys of the night sky.

You sent me a link discussing the difference between a 4 inch scope, compared to a 6 inch scope. The field of view is not what you are expecting just by reading the words "wide-field". 

Even though they are considered "wide-field".., these are amateur telescopes that point towards different positions in the sky and track those positions for an extended time as Earth rotates. (Not monitoring the entire sky).

Here's what it looks like through a 4" refractor

 

Edited January 2, 2018 by Fila

[freetoroam]

11 minutes ago, stereologist said:

Your idea of how astronomers work is rather limited. As I've mentioned in other threads there are wide field telescopes. Your comment about "covers a tiny percentage of a distant part of outer space" disregards these very important types of telescopes.

Here is a discussion concerning these scopes: https://stargazerslounge.com/topic/83925-wide-field-telescope/

These types of scopes are commonly used in surveys of the night sky.

Been here already....i do not think they want to know...are just do not understand it. Maybe it is not sci fi fantasy enough. I am getting rather tired now of this thread, going round in circles and they still do not get it.

 

[Erno86]

1 minute ago, stereologist said:

It uses the plasma as a converter and reduces the RCS while increasing other wavelength discharges. Would aliens bother to deal with radar?

I'm quite sure they would...and they most likely do --- the only drawback (as I said before) the plasma makes the shield visible --- unless they use some kind of lesser dense (less visible?) plasma that we might know nothing about --- But the plasma must be magnetically contained --- imho --- so they possibly would be still dealing with some kind of a magnetic shield of some sort.

[stereologist]

Just now, Fila said:

You sent me a link discussing the difference between a 4 inch scope, compared to a 6 inch scope. The field of view is not what you are expecting just by reading the words "wide-field". 

Even though they are considered "wide-field".., these are amateur telescopes that point towards different positions in the sky and track those positions for an extended time as Earth rotates. (Not monitoring the entire sky).

Here's what it looks like through a 6"

 

I guess you missed the part about survey telescopes. Your claim, which is wrong, is that astronomers

Quote

When Astronomers are looking through a telescope, zoomed in on a fixed location, which covers a tiny percentage of a distant part of outer space.., they look, observe the distant star formations.., and record the data.

Astronomers look at more than distant parts of outer space. They do more than "zoomed in". Surveys use wide field methods.

I'm just pointing out that  you need to get things correct. You can certainly adjust your statements using  better information - that's all.

[stereologist]

Just now, Erno86 said:

I'm quite sure they would...and they most likely do --- the only drawback (as I said before) the plasma makes the shield visible --- unless they use some kind of lesser dense (less visible?) plasma that we might know nothing about --- But the plasma must be magnetically contained --- imho --- so they possibly would be still dealing with some kind of a magnetic shield of some sort.

Why would aliens bother with radar? I see no reason to do that. It seems rather archaic for an advanced group to use.

The plasma is used to reduce the RCS. It must be reflective since it is a conductor. You say it has to be magnetically contained. Why not electrically contained? It's EM in nature.

Why bother with plasma. I'm sure there are better methods of dealing with stealth.

[Erno86]

16 minutes ago, stereologist said:

There are plenty of suggestions and that one is completely irrelevant.

I agree to disagree --- further more ---  a magnetically contained fusion plasma shielded foo fighter, should survive within the blast radius of a thermonuclear weapon, including laser particle beam and kinetic energy weapon proof!!!

Edited January 2, 2018 by Erno86
added a word

[Erno86]

Why bother with plasma?

Because the electrified plasma can be used as a weapon of mass destruction...not to mention the use for clearing out landing zones and also as a source of propulsion!!!

[stereologist]

3 minutes ago, Erno86 said:

I agree to disagree --- further more ---  a magnetically contained fusion plasma shielded foo fighter, should survive within the blast radius of a thermonuclear weapon, including laser particle beam and kinetic energy weapon proof!!!

No. LOL. So many comedians are out of work and you are telling jokes. The device would be overwhelmed easily if sufficient energy were applied to it.

[Erno86]

1 minute ago, stereologist said:

No. LOL. So many comedians are out of work and you are telling jokes. The device would be overwhelmed easily if sufficient energy were applied to it.

I'm not joking...though I have to sign-off for tonight.

Cheers

[stereologist]

3 minutes ago, Erno86 said:

Why bother with plasma?

Because the electrified plasma can be used as a weapon of mass destruction...not to mention the use for clearing out landing zones and also as a source of propulsion!!!

So now we go from things dealing with the thread and RCS to irrelevant issues with no connection to reality.

[stereologist]

This must be the new thing to say when Tesla has been typed too many times - plasma.

[stereologist]

My easily comment is similar in nature to what ChrLzs mentioned earlier. It can be done but ...

Remember I covered ground based observations. What about space junk tracking? What about systems designed to look for nuclear launches? What about UV systems that have detected ice chunks raining onto the atmosphere?

I think that the issue is a wide spectrum issue. It is not just radar and optical but a wide spectrum issue. A craft might glow in IR or leave a UV signature. Handling one portion of the spectrum is likely to lead to problems with other portions of the spectrum.