Dear Doves,
 
I would like to thank Matt for bringing up a major misconception in the understanding, or lack thereof, of just who are the Jews.  Without this understanding, it is impossible to understand anything about the Lost Tribes, and indeed to make much sense out of any prophectic scripture even aside from the Lost Tribe study.  This is not an uncommon misconception.
 
The following people are NOT JEWS...Abraham, Issac, Jacob/Israel, and ALL of the following sons and progeny of Jacob...Reuben, Simeon, Dan, Naphtali, Gad, Asher, Issachar, Zebulun, Joseph.
 
SOME of the following people are Jews...of the tribe of JUDAH, Benjamin, and Levi.
 
The House of Judah is composed MAINLY of the tribes of JUDAH, Benjamin, and Levi.  There is a small fraction of the other tribes that has been absorbed into this House of Judah, but in very small numbers.
 
The House of Israel is composed of ALL 12 tribes, but is MAINLY composed of the tribes of Reuben, Simeon, Dan, Naphtali, Gad, Asher, Issachar, Zebulun, and Joseph.  Joseph's tribe was divided into Ephraim and Manasseh, thus giving us 10 MAIN tribes in the House of Israel.
 
ALL JEWS are Israelites.  But not ALL Israelites are Jews.  This is an important distinction to grasp.  God was deliberate in His Word to distinguish between the two and so we ought to do the same.
 
Maybe this will help you to understand...All Californians are Americans, but not all Americans are Californians.
 
The term "Jews" was not used in the Bible until
 
"In the seventeenth year [as king] of Pekah, the son of Remaliah, Ahaz, the son of Jotham, king of Judah, began to reign, and reigned sixteen years in Jerusalem . . . Then Rezin, king of Syria, and Pekah, son of Remaliah, king of Israel, came up to Jerusalem to war; and they besieged Ahaz (king of Judah), but could not overcome him. At that time Rezin, king of Syria, recovered Elath to Syria, and drave the Jews from Elath; and the Syrians dwell there unto this day. So Ahaz sent messengers to Tiglathpileser, king of Assyria, saying, I am thy servant and thy son; come up and save me out of the hand of the king of Syria, and out of the hand of the king of Israel, which rise up against me," (2 Kings 16: 1, 2, 5-7).
 
Thus we have Ahaz, King of the Jews, at war against the King of Israel, and appealing to the King of Assyria to assist him AGAINST the King of Israel.  Ahaz was the King of Judah.  Ahaz was the King of the Jews.  He was NOT the King of Israel or else he was fighting against himself.
 
The term "Jews" was not used until 1200 years after Abraham.  By this time the House of Judah (Jews) and the House of Israel were well divided and have been ever since.
 
After the division of ALL of Israel into the two nations, SOME of the inhabitants of the Northern Kingdom (Israel) indeed did move into the Southern Kingdom (Judah/Jews).  Benjamin was one tribe incorporated, in large part, into Judah because their territory was encompassed by Judah.  Levy also incorporated, in large part, into Judah because of religious/political factors.  Undoubtedly, SOME members of the other Northern tribes also moved into the Southern Kingdom and were absorbed into the House of Judah.
 
The reverse is also true.  SOME members of the tribes of Judah, Benjamin, and Levi were to be found amongst the Northern Tribes and were incorporated into the House of Israel.  However, the vast majority of members of the tribes were identified according to the two Houses and their respective tribes.  The VAST majority of the House of Israel went into exile to Assyria and MOST of them never returned.  A small number did.  Just as a VAST majority of the House of Judah went into exile in Babylon with only SOME of them returning.  Many never did return.  We see today that MANY Jews have returned to the Nation Israel, but many have not.
 
Those from the House of Judah that did return are forevermore referred to as "Jews".  The Northern Kingdom House of Israel has NEVER been referred to as "Jews".  Because they aren't "Jews".  There may be some members of "Jews" within the lost tribes because they are from the tribe of Judah, but they too have lost their identity and don't know they are Jews and therefore do not identify themselves as such.  The Jews from the House of Judah never lost their identity to this day and we find them now settled in the Nation of Israel.  They themselves know they are not the House of Israel, but are the House of Judah.  But because all 12 tribes are OF Israel (just like all Californians are OF America), they are entitled to name their country "Israel".
 
So the people who are now discovering their "Israelite" identity are not calling themselves "Jews" at all.  They are calling themselves "of Israel", and it is not through wild speculation.  It is through intense and sound research of the historical, archeological, linguistic, scientific, and Biblical records.
 
I would speculate though that "...Could it be our task to see to it that the fallen
"sons of God" existing on other planets are completely destroyed?" is wild speculation.  If you have sound research on this subject, I would be happy to read it.
 
There is more detailed information on the subject of "who is a Jew?" readily available on the internet, plus it's pretty plain to me in scripture now that I know what to look for.  You might try reading this, http://www.biblestudy.org/bibleref/jsceptre/jsbp1c05.html if you are still confused.
 
So the question is, where did the lost tribes go?  They had to go somewhere.  God never forgot them and He lead them like a shepherd leads his flock.  He is going to gather them in the last days thus they are somehow identifiable.  It's a wonderful story and will enrich your life to learn about it.  Many may not want to because it doesn't pertain to them, and that's okay.
 
But as a Bible student, I always had many unanswered questions regarding prophecy in the OT.  One of them was in Genesis 49:10, "The scepter shall not depart from Judah, nor a lawgiver from between his feet, until Shiloh come; and unto him shall the gathering of the people be."  This and the other blessings given by Jacob to his son were to be for the last days. Gen 49:1.
 
Well, the scepter apparently did depart from Judah as the last king of Judah was Zedekiah who was taken and killed in the Babylonian exile.  There has not been a King of Judah since.  Jesus never took a throne while on earth and since he hasn't caused "the gathering of the people" yet, this is unfulfilled prophecy to one extent, and untrue in the sense that the scepter indeed did depart Judah, or so it seems.
 
So, is God a liar?  Heaven forbid.  We know God does not lie, therefore the scepter must have stayed with Judah.  We just lost track of where it went.
 
This is where the study of the lost tribes starts to become exciting to learn about.  Read Jeremiah again.  You will learn that after King Zedekiah and all his sons were killed, Jeremiah takes custody of the daughters of Zedekiah.  They are eventually forced to flee Egypt, but then they escape from there.  So now we have a couple of loose heirs to the title of scepter of Judah having survived captivity and murder.
 
God told Zedekiah if he didn't knock it off, He would take the scepter away from him and give it to another.  Well, Zedekiah didn't knock it off, so we have to believe God did what He said He would do and give it to another.
 
God told Jeremiah, the prophet, "See, I have this day set thee over the nations and over the kingdoms, to root out, and to pull down, and to destroy, and to throw down, to build, and to plant." Jeremiah 1:10.  Indeed, Jeremiah was right in the middle of the captivity to Babylon of the House of Judah, and the murder of Zedekiah.  He was then left the welfare of the daughters of Zedekiah to "build, and to plant."
 
So where did Jeremiah and the heirs to the scepter of Judah go?  They had to go somewhere and the narrative doesn't tell us exactly where.  But it gives us hints.  In fact, the OT is full of them.
 
And I'm not going to tell you.  This post will be too long if I do.  Any of you who are interested in this subject can research it for yourselves.  The information is out there all over the place.  But here is a hint...history has recorded for us that at least one of these daughters hooked up with and married an Israelite, and they were a King and a Queen.
 
May God Bless you all